Coastal zones are areas of ecological transition sites that enable a connection between terrestrial and marine ecosystems, through genetic and biomass exchanges, characterizing them as dynamic and biologically diverse environments (Robertson & Lenanton 1984, Monteiro-Neto et al. 2008). Sandy beaches can occur in any type of coast subject to the availability and sufficient volume of sediments to be deposited by the waves above the sea level (Veloso & Neves 2009). Many marine species, such as most of Haemulidae and the juveniles of Carangidae, use these sites for different purposes (e.g. breeding, feeding, for shelter and migration) at different stages of their development (Blaber 2002).
Surf zones may be defined as dynamic environments, characterized by the turbulence and the high energy from waves, tides and currents motion (Romer 1990). They are considered as a part of the foreshore, which is the submerged portion of the beach profile, extending from the wave break line up to the lower border of the beach face. The kind of wave break depends on the declivity of the bottom and is produced by the destabilization of the waves originated with the reduction of depth (Veloso & Neves 2009).
Studies on the ichthyofauna have demonstrated the presence of many species in surf zones, mainly in the juvenile stage, highlighting its importance for these species in this stage of life cycle (Robertson & Lenanton 1984, Godefroid et al. 2001). However, feeding and also shelter are another important use of the surf zone area by fishes (Blaber & Blaber 1980, Lasiak 1984a, b, Whitfield 1996). Fish species living in these places are represented by active planktivores, detritivores, piscivores, beach nesters and migrants from adjacent ecosystems (Moyle & Cech 2000). The understanding of the trophic relationships between species, as well as the strategies, used to reduce mortality in early stages of their life cycle can be monitored by tracking the spatial and temporal variations of ichthyofauna in sandy environments (Pessanha & Araújo 2003, Falcão et al. 2006).
Despite the relevance of the recruitment of coastal fish, there are few studies on the composition of fish assemblages in surf zones, in comparison with other coastal habitats (Wilber et al. 2003). And there is a lot of doubt about the factors that influence and control temporal variations of these assemblages in such areas (Clark et al. 1996). In Brazilian waters, researches aimed to understand the ecological role of species that reside or temporarily inhabit this ecosystem. In northeastern Brazil, for example, it can be mentioned studies on the composition of the ichthyofauna of three sandy beaches of Maceió, Alagoas (Teixeira & Almeida 1998) and Jaguaribe Beach, Pernambuco (Lira & Teixeira 2008, Santana & Severi 2009). Nevertheless, there is no publication that compares the composition and temporal variation on the fish assemblage structure in the surf zone in relation to other coastal environments, distribution of their life stages, or identification of those that are residents. Actually, most of the coastal zone is heavily human populated (Beatley et al. 2002) and the surf zones hold an increasing encumbrance as the focal area of recreation and suffer pollution from nearby urban centers (Chant et al. 2008). Determining the degree, to which surf-zone assemblages vary temporally, as well as the knowledge on the ichthyofauna in coastal areas and its use at any time, may serve as parameters for further observations and gathering of diagnoses about these sites. These information will help scientists better understand about the ecology and dynamics of the fauna, which can be critical to coastal and ocean management.
The present study aimed to characterize the ichthyofauna of the surf zone in Jaguaribe beach, Itamaracá-PE, analyzing the day and night parameters, as well as moon phases, and identifying the resident species and their seasonal use.
Material and Methods
Jaguaribe beach (Figure 1) is located in the northern portion of Itamaracá island (Pernambuco) (07° 43′ 08″ and 07° 45′ 32″ S, 034° 50′ 14″ and 034° 51′ 05″ W). It constitutes a flat area at low altitude (30-60 m) with sharp drop near the coast. The adjacent coastal marine environment, locally called “inner sea”, is sheltered by a reef line parallel to the shore, about 3-4 km from the beach front, with a profile perpendicular to it, with low declivity and maximum depth of 5 m, usually less than 2 m (Kempf 1970). The benthos are characterized by little active or dead coralline formations and encrusting coralline algae, sitting on sandstone foundation (Medeiros & Kjerfve 1993). It presents waves predominantly towards southeast, with the mainstream to the north (Santana & Severi 2009). Its substrate consists of sandy bottom with high content of calcium carbonate derived from the decomposition of the rock formation originated from coastal erosion, and sediment composed of quartz sand, shells of mollusks, foraminifera and fragments of Halimeda and Lithothamnium calcareous algae (Lopes 1999, Guerra et al. 2005). Extensive stands of seagrass beds Halodule wrightii are associated with mixed banks interspersed with Caulerpa, Sargassumand Halimeda (Kempf 1970).
Collections were performed monthly between March 2006 and February 2007, at new and first quarter moons, encompassing spring and neap tides, in day and night periods, always at low tide. A beach seine net, 20 m long, 1.5 m high and 5 mm internode mesh, was used. Two manual trawling were made in day and night periods, totaling 8 trawling/month, each lasting about 10 minutes. Trawling was parallel to the coast and towards north, at depth inferior to 1.50 m, along a 25 m segment of beach strip (07° 43′ 42.9″ S, 034° 49′ 32.1″ W).
The specimens were fixed in 10% formalin and preserved in 70% ethanol. The taxonomic identification was based on Figueiredo (1977), Figueiredo & Menezes (1978,1980, 2000),Menezes & Figueiredo (1980, 1985), Carpenter (2002a, b), Araújo et al. (2004) and Marceniuk (2005) and the classification of families according to Nelson (2006). The specimens were stored in the ichthyological collection at the Laboratory of Ichthyology, Department of Fisheries and Aquaculture, Federal Rural University of Pernambuco.
3.Rainy and dry seasons
Since the pluviometric distribution showed no well-defined pattern, the rainy season was considered as the months with rainfall exceeding 100 mm, being the remaining months regarded as dry season, according to the data obtained from Laboratório de Metereologia de Pernambuco (Laboratório… 2011). During the study period, the rainy season was established including the months from March to August of 2006 and February of 2007, and the dry season from September 2006 to January 2007.
The abundance and frequency of occurrence for each fish species were based on the pooled samples from the two trawlings made in each collection, which were analyzed per period and tide, and later grouped for the analysis per month and season (dry and wet). The combined influence of tide and period of the day on data was evaluated per month and season. The Kolmogorov-Smirnov test (P<0.05) was used to verify data normality. For normally distributed data, it was used the One-Way ANOVA and the Fisher's post hoc test (P<0.05). When the data were not distributed normally, the nonparametric tests Mann-Whitney and Kruskal-Wallis (P <0.05) were used, employing the Statistica software (Statsoft 2008).
The characterization of abundance and occurrence frequency of species was adapted from Garcia & Vieira (2001). It was considered abundant, in a certain season, the species that had a percentage of individuals (PN%) higher than the ratio 100/S, where S is the number of species present in that season. The species that had an occurrence frequency (OF%) higher than 50% at that season were considered frequent. From this point, the species were classified and grouped according to their values of PN% and FO% in: (1) Abundant and frequent (AF) (PN% ≥ 100/S and FO% ≥ 50); (2) Abundant and little frequent (ALF) (PN% ≥ 100/S and FO% <50); (3) little abundant and frequent (LAF) (PN% < 100/S and FO% ≥ 50) and (4) little abundant and infrequent (LAI) (PN% <100 /S and FO% < 50).
The abundant and frequent species (AF) were considered resident. Those that were AF both in the rainy and in the dry seasons were treated as annual resident (AR). Those which were abundant and frequent (AF), in only one of the seasons were considered resident in the dry (RD) or in the rainy season (RR), accordingly.
For the analysis of life stages and Bray-Curtis similarity, the resident species were also selected. Two phases of life were considered: juvenile and adult. To determine the age limit for adult phase, scatter plots were made with the cut corresponding to 25% of the maximum size of the species (Vazzoler et al. 1999), period at which the animal is presumably able to breed, therefore being considered an adult. Animals that were below this line were considered juvenile. The maximum size of each species (Lmax) was based on Figueiredo & Menezes (1978), Menezes & Figueiredo (1980, 1985) and Carpenter (2002a, b).
In the analysis of grouping between species, a matrix of Bray-Curtis similarity was elaborated and the data of monthly abundance were transformed by the fourth root. The results were expressed as a dendrogram, using the grouping by unweighted arithmetic mean (UPGMA), employing the PRIMER statistical package version 4.0 (Primer-E 2000).
A total of 6,407 individuals were sampled belonging to 90 species and 35 families. The families, which are most representative in number of species, were Sciaenidae (10), Engraulidae, Haemulidae (9), Carangidae (8), Achiridae, Ariidae, Clupeidae, Gerreidae (4), and Cynoglossidae (3). These nine families represented about 62% of all species caught. The 15 most numerically abundant species amounted to almost 91% of total individuals. They were Anchoviella lepidentostole,Bairdiella ronchus, Lycengraulis grossidens, Polydactylus virginicus, Larimus breviceps, Anchoa tricolor,Chirocentrodon bleekerianus, Pomadasys corvinaeformis,Stellifer stellifer, Stellifer rastrifer, Lile piquitinga, Conodon nobilis, Menticirrhus americanus,Pellona harroweri and Anchoa marinii (Table 1)
|Families (35)||Species (92)||n||PN(%)||FO(%)||C||nC||PNC(%)||FOC(%)||CC||nE||PNE(%)||FOE(%)||CE|
|Engraulidae||Anchoa tricolor (Spix & Agassiz, 1829)||244||3.81||100.00||AF||94||3.03||100||AF||150||4.53||100||AF|
|Sciaenidae||Bairdiella ronchus (Cuvier, 1830)||1192||18.60||100.00||AF||594||19.17||100||AF||598||18.08||100||AF|
|Sciaenidae||Larimus breviceps Cuvier, 1830||411||6.41||100.00||AF||294||9.49||100||AF||117||3.54||100||AF|
|Polynemidae||Polydactylus virginicus (Linnaeus, 1758)||573||8.94||100.00||AF||180||5.81||100||AF||393||11.88||100||AF|
|Engraulidae||Anchoviella lepidentostole (Fowler, 1911)||1532||23.91||91.67||AF||817||26.36||86||AF||715||21.61||100||AF|
|Sciaenidae||Menticirrhus americanus (Linnaeus, 1758)||84||1.31||91.67||AF||8||0.26||71||LAF||76||2.30||100||AF|
|Engraulidae||Lycengraulis grossidens (Agassiz, 1829)||735||11.47||83.33||AF||66||2.13||71||AF||669||20.22||100||AF|
|Haemulidae||Conodon nobilis (Linnaeus, 1758)||104||1.62||83.33||AF||30||0.97||86||LAF||74||2.24||80||AF|
|Haemulidae||Pomadasys corvinaeformis (Steindachner, 1868)||153||2.39||83.33||AF||93||3.00||71||AF||60||1.81||100||AF|
|Clupeidae||Lile piquitinga (Schreiner & Miranda Ribeiro, 1903)||111||1.73||58.33||AF||7||0.23||43||LAI||104||3.14||80||AF|
|Pristigasteridae||Chirocentrodon bleekerianus (Poey, 1867)||196||3.06||41.67||ALF||133||4.29||43||ALF||63||1.90||40||ALF|
|Sciaenidae||Stellifer rastrifer (Jordan, 1889)||142||2.22||33.33||ALF||132||4.26||29||ALF||10||0.30||40||LAI|
|Sciaenidae||Stellifer stellifer (Bloch, 1790)||175||2.73||25.00||ALF||173||5.58||29||ALF||2||0.06||20||LAI|
|Pristigasteridae||Pellona harroweri (Fowler, 1917)||79||1.23||16.67||ALF||76||2.45||14||ALF||3||0.09||20||LAI|
|Engraulidae||Anchoa marinii Hildebrand, 1943||77||1.20||16.67||ALF||0||0.00||0||-||77||2.33||40||APF|
|Hemiramphidae||Hyporhamphus roberti (Valenciennes, 1847)||43||0.67||75.00||LAF||33||1.06||71||LAF||10||0.30||80||LAF|
|Hemiramphidae||Hyporhamphus unifasciatus (Ranzani, 1841)||24||0.37||75.00||LAF||16||0.52||71||LAF||8||0.24||80||LAF|
|Carangidae||Trachinotus carolinus (Linnaeus, 1766)||18||0.28||75.00||LAF||10||0.32||86||LAF||8||0.24||60||LAF|
|Achiridae||Trinectes paulistanus (Miranda Ribeiro, 1915)||34||0.53||75.00||LAF||13||0.42||71||LAF||21||0.63||80||LAF|
|Sciaenidae||Menticirrhus littoralis (Holbrook, 1847)||21||0.33||66.67||LAF||6||0.19||43||LAI||15||0.45||100||LAF|
|Ariidae||Cathorops spixii (Agassiz, 1829)||63||0.98||58.33||LAF||53||1.71||71||AF||10||0.30||40||LAI|
|Ophichthidae||Myrichthys ocellatus (Lesueur, 1825)||10||0.16||50.00||LAF||8||0.26||57||LAF||2||0.06||40||LAI|
|Engraulidae||Anchovia clupeoides (Swainson, 1839)||16||0.25||50.00||LAF||8||0.26||43||LAI||8||0.24||60||LAF|
|Atherinopsidae||Atherinella brasiliensis (Quoy & Gaimard, 1825)||13||0.20||50.00||LAF||4||0.13||29||LAI||9||0.27||80||LAF|
|Clupeidae||Harengula clupeola (Cuvier, 1829)||14||0.22||41.67||LAI||8||0.26||43||LAI||6||0.18||40||LAI|
|Carangidae||Trachinotus falcatus (Forsskaal, 1755)||7||0.11||41.67||LAI||6||0.19||57||LAF||1||0.03||20||LAI|
|Labridae||Nicholsina usta (Valenciennes, 1840)||44||0.69||41.67||LAI||44||1.42||57||AF||0||0.00||0||-|
|Albulidae||Albula vulpes (Linnaeus, 1758)||14||0.22||33.33||LAI||9||0.29||14||LAI||5||0.15||60||LAF|
|Carangidae||Selene vomer (Linnaeus, 1758)||9||0.14||33.33||LAI||4||0.13||29||LAI||5||0.15||40||LAI|
|Achiridae||Achirus lineatus (Linnaeus, 1758)||5||0.08||33.33||LAI||2||0.06||29||LAI||3||0.09||40||LAI|
|Tetraodontidae||Sphoeroides greeleyi (Gilbert, 1785)||4||0.06||33.33||LAI||2||0.06||29||LAI||2||0.06||40||LAI|
|Narcinidae||Narcine brasiliensis (Olfers, 1831)||3||0.05||25.00||LAI||0||0.00||0||-||3||0.09||60||LAF|
|Engraulidae||Anchoa januaria (Steindachner, 1879)||30||0.47||25.00||LAI||15||0.48||14||LAI||15||0.45||40||LAI|
|Engraulidae||Anchoa spinifer (Valenciennes, 1848)||11||0.17||25.00||LAI||10||0.32||29||LAI||1||0.03||20||LAI|
|Ariidae||Sciades herzbergii (Bloch, 1794)||7||0.11||25.00||LAI||2||0.06||14||LAI||5||0.15||40||LAI|
|Belonidae||Strongylura timucu (Walbaum, 1792)||3||0.05||25.00||LAI||1||0.03||14||LAI||2||0.06||40||LAI|
|Lutjanidae||Lutjanus synagris (Linnaeus, 1758)||15||0.23||25.00||LAI||15||0.48||43||LAI||0||0.00||0||-|
|Haemulidae||Haemulon plumieri (Lacepède, 1801)||6||0.09||25.00||LAI||6||0.19||43||LAI||0||0.00||0||-|
|Haemulidae||Haemulon steindachneri (Jordan & Gilbert, 1882)||12||0.19||25.00||LAI||12||0.39||43||LAI||0||0.00||0||-|
|Labridae||Cryptotomus roseus Cope, 1871||4||0.06||25.00||LAI||3||0.10||29||LAI||1||0.03||20||LAI|
|Paralichthyidae||Citharichthys arenaceus Everman & Marsh, 1900||3||0.05||25.00||LAI||0||0.00||0||-||3||0.09||40||LAI|
|Engraulidae||Anchoa lyolepis (Evermann & Marsh, 1900)||5||0.08||16.67||LAI||4||0.13||14||LAI||1||0.03||20||LAI|
|Atherinopsidae||Membras cf. dissimilis (Carvalho, 1956)||6||0.09||16.67||LAI||2||0.06||14||LAI||4||0.12||20||LAI|
|Scorpaenidae||Scorpaena plumieri Bloch, 1789||3||0.05||16.67||LAI||3||0.10||29||LAI||0||0.00||0||-|
|Triglidae||Prionotus punctatus (Bloch, 1793)||2||0.03||16.67||LAI||1||0.03||14||LAI||1||0.03||20||LAI|
|Centropomidae||Centropomus undecimalis (Bloch, 1796)||5||0.08||16.67||LAI||0||0.00||0||-||5||0.15||40||LAI|
|Carangidae||Caranx latus Agassiz, 1831||3||0.05||16.67||LAI||1||0.03||14||LAI||2||0.06||20||LAI|
|Haemulidae||Haemulon parra (Desmarest, 1823)||18||0.28||16.67||LAI||18||0.58||29||LAI||0||0.00||0||-|
|Paralichthyidae||Etropus crossotus Jordan e Gilbert, 1882||2||0.03||16.67||LAI||2||0.06||14||LAI||0||0.00||0||-|
|Clupeidae||Ophistonema oglinum (Lesueur, 1818)||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Engraulidae||Anchoa filifera (Fowler, 1915)||4||0.06||8.33||LAI||4||0.13||14||LAI||0||0.00||0||-|
|Ariidae||Aspistor luniscutis (Valenciennes, 1840)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Batrachoididae||Thalassophryne nattereri Steindachner, 1876||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0,00||0||-|
|Holocentridae||Holocentrus adscensionis (Osbeck, 1765)||2||0.03||8.33||LAI||0||0.00||0||-||2||0.06||20||LAI|
|Syngnathidae||Microphis brachyurus brachyurus (Bleeker, 1853)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Syngnathidae||Syngnathus pelagicus Linnaeus, 1758||6||0.09||8.33||LAI||0||0.00||0||-||6||0.18||20||LAI|
|Epinephelinae||Alphestes afer (Bloch, 1793)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Mugilidae||Mugil liza Valenciennes, 1836||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Carangidae||Carangoides bartholomaei (Cuvier, 1833)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Carangidae||Carangoides chrysos (Mitchill, 1815)||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Carangidae||Chloroscombrus chrysurus (Linnaeus, 1766)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Carangidae||Selene setapinnis (Mitchill, 1815)||2||0.03||8.33||LAI||0||0.00||0||-||2||0.06||20||LAI|
|Lutjanidae||Ocyurus chrysurus (Bloch, 1791)||5||0.08||8.33||LAI||5||0.16||14||LAI||0||0.00||0||-|
|Gerreidae||Eucinostomus argenteus Bairde Girard, 1855||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Gerreidae||Eucinostomus lefroyi (Goode, 1874)||3||0.05||8.33||LAI||3||0.10||14||LAI||0||0.00||0||-|
|Gerreidae||Eucinostomus melanopterus (Bleeker, 1863)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Gerreidae||Eugerres brasilianus (Valenciennes, 1830)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Haemulidae||Genyatremus luteus (Bloch, 1790)||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Haemulidae||Haemulon aurolineatum Cuvier, 1830||12||0.18||8.33||LAI||12||0.39||14||LAI||0||0.00||0||-|
|Haemulidae||Haemulon squamipinna (Rocha & Rosa, 1999)||13||0.20||8.33||LAI||13||0.41||14||LAI||0||0.00||0||-|
|Sparidae||Archosargus probatocephalus (Walbaum, 1792)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Sciaenidae||Isopisthus parvipinnis (Cuvier, 1830)||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Sciaenidae||Stellifer brasiliensis (Schultz, 1945)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Ephippididae||Chaetodipterus faber (Broussonet, 1782)||2||0.03||8.33||LAI||0||0.00||0||-||2||0.06||20||LAI|
|Sphyrnidae||Sphyraena barracuda (Walbaum, 1792)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Trichiuridae||Trichiurus lepturus Linnaeus, 1758||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Scombridae||Scomberomorus cavalla (Cuvier, 1829)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Achiridae||Achirus achirus (Linnaeus, 1758)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Achiridae||Trinectes microphthalmus Chabanaud, 1928||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Cynoglossidae||Symphurus plagusia (Bloch & Schneider, 1801)||1||0.02||8.33||LAI||1||0.03||14||LAI||0||0.00||0||-|
|Cynoglossidae||Symphurus tessellatus (Quoy & Gaimard, 1824)||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
|Tetraodontidae||Sphoeroides spengleri (Linnaeus, 1785)||4||0.06||8.33||LAI||4||0.13||14||LAI||0||0.00||0||-|
|Diodontidae||Chilomycterus spinosus spinosus (Linnaeus, 1758)||1||0.02||8.33||LAI||0||0.00||0||-||1||0.03||20||LAI|
Figure 2 illustrates the classification of the fish species caught in the surf zone regarding their abundance and frequency in the rainy and dry seasons and year-round. Only A. tricolor, B. ronchus, L. breviceps and P. virginicus showed 100% occurrence (Table 1). It is observed that the rarest and least abundant species correspond to nearly 70% of the fish sampled.
Between dry and rainy seasons the total number of fish did not differ significantly (F = 1.39, p = 0.265). Regarding daytime and nighttime collections the total number of fish was significantly different (U = 11,500, p = 0.00048) in the annual analysis, as well as in the dry (F = 10.54, p = 0.012) and in the rainy season (U = 6,500, p = 0.02145), with the highest number of fish being found during the day in all cases analyzed. In the analysis that groups moon-day data a significant difference in the total number of fish was found (KW = 16.0337, p = 0.0011). Daytime showed a higher number of fish (5078) compared to night time (1329) in crescent and new moons. Regarding seasonality of all species analyzed, seven were annual residents (A. tricolor, A. lepidentostole, B. ronchus,L. breviceps, L. grossidens, P. virginicus andP. corvinaeformis), three were resident probably only in the dry season (C. nobilis, L. piquitinga and M. americanus) and two (C. spixii and N. usta) in the rainy season, and the latter one was recorded only in this season (Table 2).
|Conodon nobilis||Connob||RE||J, A||J, A|
|Anchoviella lepidentostole||Anclep||RA||J, A||J, A|
|Larimus breviceps||Larbre||RA||J, A||J, A|
|Polydactylus virginicus||Polvir||RA||J, A||J, A|
|Pomadasys corvinaeformis||Pomcor||RA||J, A||J, A|
Considering the life stage of species, three of them (A. tricolor, C. spixii and L. piquitinga) were recorded only in adulthood in both rainy and dry seasons. Bairdiella ronchus, M. americanus and N. usta were present only in juvenile stage. For the other species, the stages of life varied according to the season (Table 2).
The analysis of similarity between species originated two main groups separating the annual resident species (A) from the seasonal resident (B) ones, except forP. corvinaeformis, an annual resident, although it seems to have been gathered in the latter group for presenting a total abundance quite lower than that of annual resident species (Figure 3).
The grouping of annual resident species (A) was subdivided into two subgroups: one with a regular (A1) and another with an irregular distribution in the seasons (A2). The subgroup with resident species with an irregular distribution has a subgroup (A3) formed by L. grossidens and P. virginicus, which, although being annual residents, presented their abundance peak during the dry season, whileA. tricolor and L. breviceps (subgroup A4) did not show the same pattern (Figure 3).
Within the other group (B), N. usta and C. spixiii (subgroup B1) were considered residents of the surf zone during the rainy season, whereas L. piquitinga, M. americanus, C. nobilis and P. corvinaeformis formed subgroup B2, containing only the dry season resident species, except for the annual resident P. corvinaeformis. The subgroup B3, included in the latter subgroup, encompasses L. piquitinga andM. americanus which were detached from subgroup B4 because they presented low number of individuals in the rainy season (Figure 3).
The number of families (35) and species found (90) was higher than the 15 families and 25 species found by Lira & Teixeira (2008) in this same beach. Although the same fishing gear was used in both studies (beach seine net), the differences between them seem to be related to divergences in net size and collecting period, both larger in our study. This research performed manual trawling and this is the best methodology when compared with trawling realized by motor boat, once the motor noise can drive off some individuals (Pereira et al. 2010).
The occurrence of rare species is constant in surf zones (Veloso & Neves 2009). Among those recorded in the present study, some stood out for their varied life habits: Achirus achirus, Chilomycterus spinosus spinosus, Genyatremus luteus, Isophistus parvipinis, Stellifer brasiliensis, Thalassophyrne nattereri, Trichiurus lepturus, Ocyurus chrysurus, Selene setapinnis, Alphestes afer, Archosargus probatocephalus, Chaetodipterus faber, Carangoides bartholomaei, Carangoides chrysos, Holocentrus adscencionis, H. aurolineatum, H. squamipinna, Scomberomorus cavalla, Sphoeroides spengleriand Sphyraena barracuda. It is also noteworthy mentioning that the latter eleven species are usually found near or associated to reefs, and have been recorded along reef formations off the southern coast of Pernambuco and northern coast of Alagoas states (Ferreira & Cava, 2001). However, the relative occurrence of reef fish species cited above were not discussed in this manuscript as these species were considered little abundant and infrequent (LAI). The exception was N. usta, because although it was rare, was classified as annual resident.
As most of the dominant species in the surf zone (Anchoviella lepidentostole, Anchoa tricolor, Bairdiella ronchus, Larimus breviceps, Lycengraulis grossidens) form shoals and have an annual occurrence, they seem to have contributed for the total number of individuals not having differed between the dry and rainy seasons. The number of individuals was higher during the day in both annual and seasonal analysis. During the day phytoplankton activity enables a greater supply of food thus attracting many consumer individuals. Being prominently shallow regions, surf zones concentrate an even greater amount of these microorganisms (Schlacher et al. 2008). Fish species with nocturnal habits are generally predators (Helfman et al. 2009), and are less abundant than low trophic level ones. Furthermore, many carnivorous or omnivorous species are planktivorous as juveniles (Helfman et al. 2009). Considering that the surf zone is dominated by juvenile or small individuals (Robertson & Lenaton 1984), the highest total abundance for the ichthyofauna is indeed expected at daytime, independent of moon phase. Besides, fishes alter their behavior between periods by a vertical migratory activity, which bring them from near the bottom during the day into midwater at night (Beamish 1966). Differences in fish fauna composition and abundance between periods of the day also have been attributed to foraging and predator avoidance strategies (Gibson et al. 1996, Félix-Hackradt et al. 2010). The ability to shoal and the role of dominant species in total abundance associated to differences in their use of interconnected habitats throughout the day, such as estuaries/mangroves (Faunce & Serafy 2006) and seagrass meadows (Parrish 1989) in the “inside sea”, may explain the predominant abundance reduction during night period in the study area.
Among the species analyzed, seven species were considered annual residents:Anchoa tricolor, Anchoviella lepidentostole, Bairdiella ronchus, Conodon nobilis, Larimus breviceps, Lycengraulis grossidens, Polydactylus virginicus and Pomadasys corvinaeformis, as they are abundant and frequent (AF) in both seasons. ForAnchoa tricolor and Larimus breviceps the largest samples and individuals were captured at the end of the rainy season and early dry season. Within Itamaracá ecosystem, A. tricolor is characterized as a marine dependent species, which means its uses estuarine waters for feeding or to accomplish a late phase of its reproductive cycle (Vasconcelos Filho & Oliveira 1999), and Larimus breviceps was also regarded as resident by Fagundes et al. (2007) in the surf zone of Santos Bay, São Paulo. It is probable that Anchoa tricolor inhabit the surf zone and spawn in the estuary, also used for nursery and recruitment phases (El-Deir 2005). Larimus breviceps might use this area as a nursery as well and when adult (late rainy season and early dry season) migrate to areas of greater depth known on the Island of Itamaracá as “outer sea”.
The species Anchoviella lepidentostole and Bairdiella ronchus were found in the surf zone during almost the whole period of the study, with the later one being represented mainly by juveniles. Both are common in ichthyofaunal surveys for this ecosystem in other areas of the Brazilian coast (Godefroid et al. 2004, Oliveira-Neto et al. 2008). HoweverA. lepidentostole was not recorded on the assessment of ichthyofauna conducted with the same fishing gear on Jaguaribe beach (Lira & Teixeira 2008) and in the Channel of Santa Cruz (Vasconcelos Filho & Oliveira 1999), both located on Itamaracá Island. This might be due to the lower sampling effort evidenced in these studies in relation to the present one, sinceA. lepidentostole is commonly found in estuarine areas along the Brazilian coast (Paiva Filho et al. 1986, Paiva Filho & Giannini 1990, Chaves & Vendel 2008), including Pernambuco (Paiva & Araújo 2010). Concerning the use of estuaries, A. lepidentostole is a semi-anadromous fish and its arrival in the estuary is through shoals composed by older individuals, whereas the younger ones remain in the sea to feed and grow, entering the estuary later, when they reach sexual maturity (Camara et al. 2001). B. ronchus has been regularly recorded to breed in this ecosystem (Chaves & Bouchereau 2004). The surf zone is used as a feeding and growing ground (Santana & Severi 2009) by A. lepidentostole, as well as a nursery area byB. ronchus. This species is known to use different coastal habitats for completion of the reproductive cycle, such as mangroves, estuaries and adjacent coastal environments, as previously reported elsewhere (Chaves 1995, Castro et al. 1999). Due to the predominance of juveniles throughout the whole year, it can be stated that Polydactylus virginicus uses the surf zone as a nursery and growing place as the species cited above. Adults occurred in a smaller number and had two peaks, one at the beginning and another one at the end of the dry season. These might be the periods when they migrate to marine demersal regions, where they complete their life cycle. The individuals that live in demersal areas of some parts of the Brazilian coast (Souza & Chaves 2007, Moraes et al. 2009) have larger sizes than those found in this study.
Regarding the occurrence of life phases between seasons, a different pattern was observed in the resident species Lycengraulius grossidens and Pomadasys corvinaeformis in the study area. L. grossidens is a marine (Anacleto & Gomes 2006) and estuarine (Schifino et al. 2004) species, and is well distributed in the estuaries of Pernambuco (Paiva & Araújo 2010), including that of Jaguaribe river - Itamaracá (El-Deir 2005). In our study, only adult individuals were found in the rainy season and only juveniles in the dry season. In the estuary of Lagoa dos Patos (RS), eggs and larvae of this species are the most numerous and abundant ones among the collected species. They occur during the summer because water temperature, instead of salinity, presents a stronger influence on spawning (Anacleto & Gomes 2006).
During the rainy season in the northeastern region, adult fish might use the surf zone to feed and then migrate to the estuary at the end of this season. The recruitment in the surf zone occurs during the dry season. The opposite was recorded for Pomadasys corvinaeformis. This species inhabits demersal, marine and estuarine areas (Cervigón 2003), with records for the Jaguaribe river estuary (El-Deir 2005), Itamaracá. Although juveniles prevailed during the rainy season, January represented the peak for this life phase, and the predominance of adults occurred during the dry season. The results of this study corroborate with those of Costa et al. (1995) on the coast of Ceará, which associated the abundance of the species with rainfall. However, Chaves (1998) disagreed with Costa et al. (1995) because the abundance of the species in Guaratuba Bay (PR) depended more on the reduction of water temperature rather than the pluviometric indicators. It is noteworthy the divergences between the climates of the two areas, given that there are only two seasons in northeast and four in south Brazil, which make difficult a direct ecological comparison.
In this study, five species showed seasonal residence: Cathorops spixii, Conodon nobilis, Lile piquitinga, Menticirrhus americanus and Nicholsina usta. Cathorops spixii and N. usta were considered resident of the rainy season. The first one is the most common catfish species on the Brazilian coast, preferably living in estuaries (Carvalho-Filho 1999). In the Channel of Santa Cruz, Itamaracá, this species is known to spend its entire life cycle in such environments, but it can also be found in coastal marine habitats and fresh waters (Vasconcelos Filho & Oliveira 1999). Its residence on the rainy season, corroborating with Lira & Teixeira (2008), was represented only by adult individuals in the surf zone, with a peak between May and July. According to Chalom et al. (2008), C. spixii is opportunistic, eating most of the available food in the environment, and shrimp being one of the most representative items of its diet. Therefore, the large amount of specimens found in the rainy season in Jaguaribe beach seems to be related to the high abundance of penaeid shrimp, also found during this season in the surf zone, in accordance with personal observations made throughout this research. Differing from C. spixii, N. usta is characteristic of coral reefs (Randall 1990), occurring in the surf zone exclusively in this season. Only juvenile individuals represented this species, with its peak in March and April. The species lives associated with marine phanerogam meadows (Arrivillaga & Baltz 1999, Ordoñez-López & García-Hernández 2005, Allen et al. 2006, Prado & Heck Junior 2011). Since there is no record of this species in the estuaries of Pernambuco (Paiva & Araújo 2010), and the surf zone of Jaguaribe beach is rich inHalodule wrightii marine phanerogam (Kempf 1970), the species possibly migrates from the reef areas to graze in the surf zone during its recruitment period.
Some species had higher frequency in a determinate season. These were the case ofLile piquitinga and Menticirrhus americanus. Lile piquitinga is a characteristic species of the Northeastern region (Figueiredo & Menezes 1978). It occurred in the surf zone of Jaguaribe beach, even though it was not registered in this site by Lira & Teixeira (2008). Considered as marine dependent on the Santa Cruz Channel estuary (Vasconcelos Filho & Oliveira 1999), it is widely found in the estuaries of Pernambuco (Paiva & Araújo 2010). In the surf zone, it was represented by adults and showed a well-defined seasonal pattern of occurrence, being frequent in the dry season, with its peak in December. In the Jaguaribe River estuary, this species was found in the rainy season (El-Deir 2005), suggesting that it is using the estuary in this season and the surf zone during the dry season, before migrating to deeper areas. Differently, M. americanus, represented only by juveniles, was little abundant, although frequent in the rainy season, and abundant and frequent during the dry season. The results of this study indicate the surf zone as a nursery area for this species, corroborating with Godefroid et al. (2001), who noted the presence of larvae and juveniles in Pontal do Sul beach (PR). Adults do not usually occur in the surf zone, but are regularly caught in deeper water (Souza & Chaves 2007). The species depends on the estuary to complete its reproductive cycle (Vasconcelos Filho & Oliveira 1999), and has been recorded in several estuaries of Pernambuco (Paiva & Araújo 2010). M. americanus possibly alternates the type of ecosystem used as nursery, according to the season of the year: the surf zone (dry period) and estuary (rainy period).
The haemulid Conodon nobilis was represented in both seasons, mainly by juvenile individuals, with its peak in January (end of the dry season). Adults of this species are commonly caught incidentally in demersal areas during shrimp fishing (Vianna et al. 2004, Souza & Chaves 2007), considering that juvenile individuals might use the surf zone as nursery, and the month of January being the recruitment period. In the region of Itamaracá, this species was considered as a visitor to the Santa Cruz Channel (Vasconcelos Filho & Oliveira 1999) and as frequent in Jaguaribe beach (Lira & Teixeira 2008), corroborating with the present study.
Although not being a resident species in either of the seasons, some species showed a defined pattern of occurrence, such as Chirocentrodon bleekerianus, Hyporhamphus roberti, Stellifer rastrifer and Trinectes paulistanus. Chirocentrodon bleekerianus presented a regular abundance in determinate months (July to October). It is a characteristic species of coastal areas (Carvalho-Filho 1999), but there are only two previous records for the coast of Pernambuco (Lira & Teixeira 2008, Santana et al. 2009). Adults might reach the surf zone in search for food, as they eat some fish and crustaceans (Corrêa et al. 2005), preys commonly found in this ecosystem. The time of higher incidence of C. bleekerianuscoincided with the peak of juvenile Engraulidae and post-larvae of penaeid shrimp (personal observation) in this season (July-October). Stellifer rastrifer also prey on penaeid shrimp (Camargo & Isaac 2004), and has its peak of abundance coinciding with the time when the peak of such prey occurred (in August). This species occurs in coastal shallow waters (Carvalho-Filho 1999), characteristic of estuarine areas (Araújo et al. 2004), being registered in the Santa Cruz Channel (Vasconcelos Filho & Oliveira 1999). It is occasionally found in Jaguaribe beach (Lira & Teixeira 2008, Santana & Severi 2009). This species occurred from July to October, peaking in August, being represented by juvenile and adults.Hyporhamphus roberti was represented only by adults during the year of study, peaking in July. As this species occurs in estuarine areas (Carpenter 2002a), having been recorded in the estuary of Jaguaribe River (El-Deir 2005), it probably comes to shore to eat shrimps, which are abundant in the rainy season (personal note). Hiatt & Strasburg (1960) cited in Randall (1967) reported small fish and planktonic crustaceans as food items for fish of this genus. Trinectes paulistanus was little abundant in Jaguaribe beach, corroborating with Mendonça & Araújo (2002) that analyzed the temporal distribution of this species in Sepetiba Bay (RJ). It occurs in estuarine and marine environments (Figueiredo & Menezes 2000), being present in the northeastern coast (Araújo et al. 2004). Only the adults occupied the surf zone in both seasons (wet and dry). The occurrence of larvae and juveniles of this species is recorded in estuarine areas (Michele & Uieda 2007), whereas adults inhabit different areas, including shores (Godefroid et al. 2004). The species possibly uses the surf zone environment as an intermediary one between the Jaguaribe River estuary and the “outer sea”.
Coastal marine systems are among the most ecologically and social-economically vital ones for the planet, therefore subject to the cumulative effects of global change, including climate change, increased population, pollutant discharge and eutrophication (Harvey et al. 2006, Rabalais et al. 2009). Thus, estuarine and coastal waters are potentially bound to biodiversity loss and community disruption, with unpredictable consequences on fish stocks and fishery sustainability, unless surf zones' role on coastal fishes' life cycle is better understood and incorporated in conservation practices and environmental management actions.
The surf zone of Jaguaribe beach presents an ecological importance as it encompass a great diversity of fishes, including species considered rare for this ecosystem, as well as species which are resident annually or seasonally. The distribution patterns of species found in this study show that the ichthyofauna of the surf zone in Jaguaribe beach is rich, mainly dominated by small-sized individuals including juvenile phase of several species, with the presence of species most commonly found in neighboring environments, such as seagrass beds, estuaries and reefs. The role of surf zones as an integrated component of interconnected environments in coastal areas of Pernambuco, and their function in the life cycle of coastal fishes is probably a common ecological pattern for the beaches on tropical coastal.