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

Abstract

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.

Identification of potential fish stocks and lifetime movement patterns of Mugil liza Valenciennes 1836 in the Southwestern Atlantic Ocean

“…Even though different movement behaviors were observed for the studied mullet species, none of the patterns were specific of a studied area. This could be associated to the migratory capability of the species, but there is a need to revise more in depth the reproductive cycle of M. liza linked to the studied wetlands as it has been done for other areas preferred by this species like Lagoa dos Patos or Santa Catarina Region in Brazil (Herbst and Hanazaki, 2014;Viera, 1991). It is also important to consider that the low number of fish studied by area for life history patterns could be masking other patterns that could have been found with a more abundant otolith sample.…”

Trophic relationships between people and resources: fish consumption in an artisanal fishers neighborhood in Southern Brazil

“…This migratory behavior from a freshwater environment to a saltwater environment is highlighted in the respondents reports, which they state influences the taste, which was also reported in other studies (Herbst and Hanazaki 2014; Murrieta 1998; Souza and Barrella 2001). The presence of this fish during the winter season generates much expectation in the coastal communities and involves a special organization of fishers (Herbst and Hanazaki 2014), leading to an increase in the consumption of this species during the winter season. The period when data was collected must have been influenced by this seasonality; and we have to consider that any sampling method carries inherent biases unless we could distribute the sampling effort including several conscutive days all over the year.…”

No mullet, no gain: cooperation between dolphins and cast net fishermen in southern Brazil

“…No significant seasonal variations of mullet abundance were observed. This is unusual because it is known that in periods of reproductive aggregation of M. liza the catches of artisanal fisheries increased notably (Vieira et al 2008, Herbst and Hanazaki 2014. This may be associated with the way cast nets operate and the fishing dynamics.…”

“…Only in summer the fishermen significantly catch larger mullets when bottlenose dolphins are present. This can be explained by the fact that after the reproductive period (autumn/winter) adult individuals of M. liza move from the marine environment to the estuaries and coastal region of southern Brazil in small and sporadic schools, mixing with juvenile individuals (Herbst andHanazaki 2014, Lemos et al 2014). In this work, the size analysis of individuals caught in summer showed a predominance of juveniles and the occurrence of few adults, only.…”

“…According to them, the decrease in water temperature and the increase in salinity in the estuaries, associated with the southern wind that promote the intrusion of marine water in estuaries during the austral autumn act as "triggers" for sexually mature individuals of M. liza runs to the ocean. In this reproductive migration period, called the 'corrida da tainha', artisanal fishermen intensify fishing efforts throughout the southern Brazilian coast, raising the quantities of mullets caught within the estuaries (Vieira et al 2008, Herbst and Hanazaki 2014, Lemos et al 2016, Sant'Ana et al 2017. Nevertheless, water temperature and salinity did not have representative effects on the explicability of the models of occurrence and abundance of mullet in the cast net fishery at TRE.…”