Local ecological knowledge of fishers about the life cycle and temporal patterns in the migration of mullet (<i>Mugil liza</i>) in Southern Brazil

Herbst, Dannieli Firme; Hanazaki, Natalia

doi:10.1590/1982-0224-20130156

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Articles • Neotrop. ichthyol. 12 (4) • Oct-Dec 2014 • https://doi.org/10.1590/1982-0224-20130156 copy

Local ecological knowledge of fishers about the life cycle and temporal patterns in the migration of mullet (Mugil liza) in Southern Brazil

Authorship SCIMAGO INSTITUTIONS RANKINGS

This research investigates local ecological knowledge of fishers in communities along a latitudinal gradient in the coast of the Santa Catarina State, regarding the life cycle of mullets Mugil liza (migration, feeding, and reproductive behavior). Our sampling encompassed eight Santa Catarina coastal cities (nine artisanal fishing sites) and engaged 45 key informants (28- 86 years of age) through semi-structured interviews from August/2011 to March/2012. This fish species feeds and grows in lagoon and estuarine systems, migrating to the sea for reproduction, and spawning. Fishers acknowledged the Patos Lagoon and the Plata River as the main source of mullet schools. Migration occurs from South to North and the routes vary according to climatic and oceanographic conditions (e.g., low temperatures, south winds, rainfall, currents, salinity). These conditions influence the abundance of mullets (and therefore fisheries success), their migration and stops in locations such as beaches, rocky shores, and islands. According to fishers, mullet spawning occurs throughout the coast of the Santa Catarina State and they feed in lagoons and riverine systems but also out at sea during migration. In conclusion, fishers possess a detailed knowledge about mullet life cycle and they identify intra and interannual variations in migration routes, a pattern that should be considered in managing the fishery.

Artisanal fisheries; Ethnoecology; Feeding; Mugilidae; Reproductive biology

Ecological aspects addressed	Questions
Migration	Why mullets migrate? Whence and whither? When they go out to the sea? Is there a route where the school goes?
	What are the main fishing sites in coastal Santa Catarina State? What is the ideal condition for mullet migration?
Reproduction	Are there differences between male and female? How do you know which is male and which is female? When is
	the breeding season? How far in life it becomes mature (adult, ready to breed)? What size they have at the
	moment? How is the reproductive process? How long it stays with eggs? When and how the eggs are released?
	Where do they spawn? What is the best condition for mullet spawning?
Feeding	What do they eat? When and where they feed?
Interactions	How does mullets interact (behaviors within the group)? They interact with other species? Do you know some
	sort of parasite or disease in mullets?

Environmental condition	Citations	Description
South wind (low temperatures)		‘The more wind and colder, more the mullet runs’ (Imbituba fisher, 39 years old). ‘If
	38	you have south wind and sea current that helps, in 5-8 days the mullet is on the coast
		of Santa Catarina State’ (Pinheira fisher, 75 years old)
Weak north/northeast wind	35	‘With south wind they come out, but when that stops and turns to northeast wind
		they seek the coast’ (Garopaba fisher, 72 years old)
Southwest or offshore wind (‘minuano’	08	‘What send the fish to the north is the offshore wind, west wind, because further
or ‘terral’)		south it gets too cold’ (São Francisco do Sul fisher, 33 years old)
Rebojo (agitated sea)	07	‘When it hits the Rebojo, bad weather, the mullet takes to travel’ (São Francisco do
		Sul fisher, 57 years old)
Rain	02	‘When storm happens then the fish ends, they pass far from the coast’ (Garopaba
		fisher, 56 years old)
Full moon (full tide)	02	‘If it’s a full moon with south wind and is May 1^st to 15^th the mullet comes’ (Pinheira
		fisher, 42 years old)
New moon	01	‘The strength of the new moon makes the mullet leave outward at Rio Grande [Patos
		Lagoon]’. (São Francisco do Sul fisher, 57 years old)

Reason for stop	Citations	Description
Resting	15	‘They stop to rest, and keep playing and jumping’ (São Francisco do Sul fisher, 57 years old)
Spawning	14	‘They only stop where the bottom has stone or coral, slime to eat. And in the slime of the
		stones remains only those little heads [eggs]’ (Pinheira fisher, 42 years old)
Feeding	12	‘To eat, because the waters hit the algae and is best for them to eat and to create fat’
		(Bombinhas fisher, 55 years old)
Warm temperature	04	‘They wait for the wind. With north wind is difficult to leave the rocky shore, but when the
		south wind comes they leave’ (Pântano do Sul fisher, 68 years old)
Protection from predators	03	‘They seek refuge where the fishers cannot catch them. They can be stopped for months on
		the rocky shores, if nobody can fish them’ (Barra da Lagoa fisher, 48 years old). ‘They stop
		afraid of predators, dolphins, other fish’ (Bombinhas fisher, 86 years old)

Aspects about the reproduction		Citations	Description

a)	Reproductive process	12	‘The mullet gets the belly-up, silver. Then you see from afar, they rub the belly
			one on another’ (Bombinhas fisher, 55 years old); ‘the meeting of eggs and
			sperm is into the water, which will later stick to the scales of the fish’ (Barra
			da Lagoa fisher, 39 years old).
b)	Different gonadal stages	03	At the start of fishing the gonad is yellowish and thin. At the end of June the
			gonads are quite larger and thicker. By August the gonads lose flavor and are
			redder and in September the roes are hatch under the fish scales. November
			there is no gonads or with a very thin roe to be filled again in April and May,
			when we start fishing again’(São Francisco do Sul fisher, 54 years); ‘By May
			the gonad is yellow, like a mass, by June you eat the little grains and by
			August it is already bad’ (Bombinhas fisher, 86 years old).
c)	Spawning sites	Sea (17); River and	‘They spawn in rocky shores, but also within the lagoon. Those who enter in
		lagoon (3);	the lagoon hide in the grass to breed, and nobody sees them’ (Bombinhas
		Sea, river and lagoon	fisher, 62 years old); ‘[…] when they do not find a river, they spawn in the
		(19)	beach’ (Bombinhas fisher, 86 years old).
d)	Spawning process	30	‘The mullet shivers the scales and the cubs are down the scales until they reach
			a stage that they can feed and protect themselves. She lets out a protection, oozing, gelatinous’ (Pantano do Sul Fisher, 52 years); ‘The mullet was smeared, half red, and it was different, like whity and burst as if a varicose vein. In the whole body. They put [the spawn] down the scales to protect from other fish’ (Barra da Lagoa fisher, 48 years); ‘She seeks those grasses and stays there, quietly, hatching. It’s rare, you see one in 1000’ (São Francisco do Sul fisher, 74 years); ‘There are two or three little eggs under each scale […]. If you look well you can see even the little eyes of the juveniles […] She gets all soft, silly, just moved her mouth (Bombinhas fisher, 79 years); ‘I've seen the roes on the scales, but they say it is a disease that occurs in the mullet…’ (Pântano do Sul fisher, 59 years).

Breeding locations	Citations	Description
Return to Patos Lagoon	15	‘Juveniles go along with their mother, to enter the lagoon back’ (Garopaba fisher, 44 years
		old).
Return to rivers and lagoons	10	‘The mullet spawns and then the juveniles go back to the same place where the mother left,
		should be a memory that stays with the juvenile (Pântano do Sul fisher, 52 years old).
Live in rivers and lagoons	10	‘The mullet spawns and juveniles go to nearest mangroves, rivers and lagoons (Pântano do Sul
close to the spawning site		fisher, 53 years old).

Food item	Citations	Description
Sand and mud	21	‘They eat sand and mud. When we fished in the lagoon it tastes like mud. During the migration,
Slime, sludge and peri grass		they clean up at sea, and then is delicious’ (Pinheira fisher, 75 years old).
Slime, sludge and peri grass	21	‘They eat in the peri grass’ (Pântano do Sul fisher, 78 years old). ‘They stay nibbling the slime
(Cyperaceae, common in the		and sludge from rocky shores and fishing nets’ (Pântano do Sul fisher, 29 years old).
lagoon margins)
Boat oil	11	‘In polluted places, they suck the oil, especially the boat oil and they acquire this taste to the
		flesh’ (Barra da Lagoa fisher, 48 years old).
Algae	10	‘They eat sea algae, plankton, slime foam on the rocky shores’ (São Francisco do Sul fisher, 83
		years old).
Plankton	08	‘They eat plankton, this mixture of small things’ (Barra da Lagoa fisher, 39 years old); ‘When
		they stop at the shore they eat plankton’ (Pântano do Sul fisher, 53 years old).
Invertebrates and larvae	05	‘I've seen it stops at the beach and eat shellfish larvae’ (São Francisco do Sul fisher, 57 years
		old); ‘They eat mole crabs (Emerita brasiliensis) and small animals’ (Garopaba fisher, 56 years
		old)

Sociedade Brasileira de Ictiologia Neotropical Ichthyology, Núcleo de Pesquisas em Limnologia, Ictiologia e Aquicultura, Universidade Estadual de Maringá., Av. Colombo, 5790, 87020-900, Phone number: +55 44-3011-4632 - Maringá - PR - Brazil
E-mail: neoichth@nupelia.uem.br

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