ABSTRACT
This study investigated whether variations in climate and ocean drivers on global, regional, and local scales affected macrozooplankton communities in a coastal protected area in Tamandaré Bay (northeastern Brazil). For this purpose, bimonthly field campaigns were carried out from June 2013 to August 2019. A significant tipping point (point of change, p < 0.001), with an abrupt increase in SST, was detected in the TSA (Tropical South Atlantic) index. This indicates the existence of a climate regime shift in the Tropical South Atlantic during the 2015/16 El Niño (EN) event. Extreme rainfall events were observed in Tamandaré Bay after this EN event, in 2017, 2018, and in 2019 (and more recently, in 2022). This extreme rainfall led to low-salinity events, increased variability in salinity, and significantly lower abundances in the period after the strong EN event, for socioeconomically relevant penaeid shrimp postlarvae and several other zooplankton groups (e.g., copepods, appendicularians, anomuran hermit crab larvae, and chaetognaths). We found a significant relationship between SSTs in the TSA region and penaeid shrimp recruitment in the study area, located leewards of the TSA index area. The decline in shrimp postlarvae and other macrozooplankton may be due to a combination of factors, such as climate and ocean shifts (atmospheric easterly waves disturbances, winds, precipitation, salinity) and possibly increasing marine pollution (related to extreme rainfall events, that convey macro- and microplastics, and pollutants from the continent). Cnidarian medusae and fish eggs were among the few "winners" of this ecosystem regime shift. Changes in climate, ocean, macrozooplankton, and shrimp postlarvae abundance evidence a relevant climate, ocean and ecosystem regime shift in this region with a tipping point during 2015/16 "Godzilla" El Niño. Possible future consequences in the context of persistent warming in the TSA region and the currently ongoing record strength 2023/24 EN event are discussed.
ABSTRACT
A carcinofauna dos ambientes marinhos e costeiros das regiões sudeste e sul da Bahia, Brasil, ainda é pobremente conhecida. O objetivo deste estudo foi realizar um inventário da fauna de crustáceos decápodos do município de Ilhéus, localizado no sudeste da Bahia (14º47'55"S, 39º02'01"W). As amostragens foram realizadas de Fevereiro de 2001 a Fevereiro de 2005, nas zonas supra, meso e infralitoral. Os exemplares coletados foram fixados em etanol 70 por cento e depositados na coleção de crustáceos da Universidade Estadual de Santa Cruz, Ilhéus (MZUESC). Foi coletado um total de 51 espécies pertencentes a 14 famílias. A família mais representativa em termos de número de espécies foi Ocypodidae, representada nas amostragens por 8 espécies. A distribuição geográfica conhecida para as espécies Alpheus heterochaelis (Caridea: Alpheidae), Merguia rhizophorae (Caridea: Hippolytidae) e Sesarma curacaoense (Brachyura: Sesarmidae) foi estendida. A ocorrência do siri exótico Charybdis hellerii, originário do Indo-Pacífico, foi registrada para o estuário do rio Cachoeira. Estes resultados indicam que os estuários de Ilhéus abrigam elevada riqueza de espécies.
The carcinofauna from marine and coastal environments from the southeast and southern Bahia, Brazil, is so far poorly known. The objective of this study was to survey decapod crustaceans occurring along the estuarine environments of Ilhéus, located on the southeast coast of Bahia (14º47'55"S, 39º02'01"W). Samplings were carried out from February 2001 to February 2005, covering supratidal, intertidal and subtidal habitats. Voucher specimens were fixed in ethanol 70 percent and deposited in the collection of Crustacea of the Universidade Estadual de Santa Cruz, Ilhéus (MZUESC). We report a total of 51 species, belonging to 14 families. The most representative family concerning the number of species was Ocypodidae, represented in our samples by 8 species. Geographic range known for the species Alpheus heterochaelis (Caridea: Alpheidae), Merguia rhizophorae (Caridea: Hippolytidae) and Sesarma curacaoense (Brachyura: Sesarmidae) was enlarged. The Indo-Pacific portunid crab Charybdis hellerii was recorded for the Cachoeira river estuary. The results indicate a high species richness of decapod crustaceans in the estuarine environments of Ilhéus.