Morphometric variation in pink shrimp populations at Rio de Janeiro coast (SE Brazil): are they really similar in closer areas?

Abstract

Farfantepenaeus brasiliensis and F. paulensis are the most exploited shrimps of Se-S Brazilian coast. Our aim was to verify if adjacent nursery areas with different environmental condition (Sepetiba and Guanabara bays, SE Brazil) influence on shrimp populations (eg, CPUE) and body shapes. Samplings were carried out during 12 months in those bays ca. 85 Km far from each other. Carapace length (Cl), total body length (Tl), wet weight, abdomen size and Tl/Cl ratio were used to analyze variations in shape through regressions. In general, F. brasiliensis was 4 to 6 times more abundant than F. paulensis. The sex ratio differed from 1:1 in F. brasiliensis in both bays, with dominance of females, largest catches occur in autumn. However, differences in size and morphology were found between bays, mainly regarding the Tl/Cl ratio. Shrimps in Sepetiba Bay have higher Tl/Cl showing a more "elongated shape" (larger abdomen) when compared to those from guanabara Bay. Results suggest the existence of an estuary vs shrimp morphology relationship which results in differences in body shape even in spatially close areas. TL/CL ratio has proven useful for assessing shrimp populations differences and might be tested for tracking the origin of adult shrimps stocks at the coast.

Biometric relationships and sex ratio for red-spotted shrimp Farfantepenaeus brasiliensis (Latreille, 1817) (Decapoda, Penaeidae) from the coast of Sergipe, northeastern Brazil

“…As most organs of shrimps, including the reproductive ones, are located in the carapace, differences between sexes in the TL/CL ratio are expected, with females having a proportionally larger carapace than males as an adaptation to maximize egg production. Indeed, these differences in the TL/CL ratio are not observed when analyzing juveniles (Carvalho et al, 2019).…”

“…Morphometric relationships vary according to the length/age, with younger, smaller individuals having higher slopes than older, larger individuals requiring different equations for conversions (Arreguín-Sánchez, 1981;Primavera et al, 1998;Reis-Jr et al, 2019). Most of the morphometric data available for F. brasiliensis are from juveniles/subadults inhabiting coastal habitats such as estuaries and coastal lagoons (Villela et al, 1997;Branco and Verani, 1998;Pérez-Castañeda and Defeo, 2002;Albertoni et al, 2003;May-Kú et al, 2006;Freitas-Jr et al, 2011;Carvalho et al, 2019), which differ from the equations for adults such as the ones obtained here in the coast of Sergipe. Table 2.…”

“…Several population studies have estimated biometric relationships for penaeids and these relationships have been highlighted as an important tool for assessing the status of shrimp stocks, as very often different morphological traits may ref lect environmental influences or overfishing impacts (Leite-Jr and Petrere-Jr, 2006;Dumond and D'Incao, 2010;Segura and Delgado, 2012;Silva et al, 2015Silva et al, , 2018Reis-Jr et al, 2019). Biometric relationships for F. brasiliensis have already been estimated for southern and southeastern Brazil (Mello, 1973;Villela et al, 1997;Branco and Verani, 1998;Albertoni et al, 2003;Leite-Jr and Petrere-Jr, 2006;Carvalho et al, 2019) as well as for the Gulf of Mexico (Arreguín-Sánchez, 1981;Pérez-Castañeda and Defeo, 2002;May-Kú et al, 2006). Nevertheless, there is no information about this species for northeastern Brazil.…”

Ficha de Farfantepenaeus paulensis

“…Ao comparar populações de sub-adultos de F. brasiliensis e de F. paulensis em dois sistemas estuarinos próximos no estado do Rio de Janeiro, Carvalho et al (2019) observou diferenças interespecíficas em relação ao tamanho e a morfologia dessas espécies indicando uma grande plasticidade fenotípica, apesar da ausência de variabilidade genética significativa na costa sudeste brasileira (relatada até o momento). A forma mais alongada do abdômen a partir da relação comprimento total (CT) versus comprimento da carapaça (CC) dos camarões-rosa capturados na Baía de Sepetiba em relação aos obtidos na Baía de Guanabara, sugeriu que o desenvolvimento morfológico ao longo da ontogenia desses peneídeos está intimamente relacionado às condições ambientais das áreas de berçário.…”

Morphological discreteness of the estuarine croaker Pseudotolithus elongatus (Teleostei: Sciaenidae)

“…It has been used in a wide range of ecological studies to differentiate taxonomic groups and determine if there are multiple stocks in a population which can be beneficial to stock assessment (Asuquo & Ifon, 2019;Cronin-Fine et al, 2013;Elliott et al, 1995;Marramà & Kriwet, 2017;Schaefer, 1992). The morphometric approach has been reported to be very economical, yet highly effective in stock assessment (Carvalho et al, 2019;Ferrito et al, 2007;Hanif et al, 2019;Rios et al, 2019). Studies, including those of Schaefer (1992) and Elliott et al (1995), have shown that traditional morphometric tool is better than truss network and can be used conveniently where DNA analysis is not available.…”