Length–weight relationships for 22 crustaceans and cephalopods from the Gulf of Cadiz (SW Spain)

Abstract

Life history traits are available for many fish species in different regions, but less so for invertebrates such as cephalopods and crustaceans, though, they are increasingly needed for implementing an ecosystem-based approach. Recent food web modelling in the Gulf of Cadiz has identified invertebrates as keystone groups. However, information on life history traits of such groups remains incomplete in this region. To fill this knowledge gap, we report length-weight relationships for 12 cephalopods and 10 crustaceans collected in the Gulf of Cadiz from 2009 to 2013. This study reports, for the first time, life history traits of nine species in the area (Chlorotocus crassicornis, Pasiphaea sivado, Plesionika heterocarpus, Plesionika martia, Processa canaliculata, Solenocera membranacea, Allotheutis media, Sepia orbignyana and Sepietta oweniana). For each species, length-weight relationships, minimum and maximum lengths, mean weights, and depth ranges are presented. Overall, the results revealed that all species showed negative allometric growth (hypoallometry), except P. sivado, the only species showing an isometric growth pattern. We expect that this study will contribute to link sustainable fisheries with biodiversity conservation goals enabling the implementation of operational ecosystem-based management in the Gulf of Cadiz.

Length weight relationships of coleoid cephalopods from the eastern Mediterranean

“…Although LWR is widely used and known for fish, it is poorly understood for non-fish species 5 . In fact, cephalopods particularly should be investigated carefully for LWR studies as they have unique life history traits such as semelparity, sexual dimorphism (extreme in some species e.g.…”

A review of recent studies on the life history and ecology of European cephalopods with emphasis on species with the greatest commercial fishery and culture potential

“…The latter study also shows that, at least in the Adriatic Sea, S. orbignyana has group-synchronous ovulation and the species is most probably an intermittent terminal spawner. It was found that weight-length relationships of both sexes exhibit slower relative growth in weight than in length (b = 2.46 in males and b = 2.62 in females), which corresponds to the growth patterns seen in the Gulf of Cadiz, although the scaling exponent b reaches only 2.38 in the latter case (Torres et al, 2017).…”

“…Weight-length relationships for E. cirrhosa and E. moschata in South West Iberian waters (Gulf of Cádiz) were similar, although the scaling exponent b was lower in E. cirrhosa (b = 2.34) than in E. moschata (b = 2.70) (Torres et al, 2017).…”

“…Weight-length relationships were studied in common cuttlefish from Southern Portugal (Vasconcelos et al, 2018). A slower relative growth rate in weight than in length (scaling exponent b<3) was reported, which is a common feature of short-lived species (Torres et al, 2017). Vasconcelos et al (2018) concluded that this feature is the result of high feeding rate and high food conversion efficiency.…”

“…These authors recommended the use of COI rather than 18 s rDNA for species barcoding due to higher bootstrap support of species clusters and less amplification and sequencing failure for this gene. One study during the review period concerned the weight-length relationship of the bobtail squid inhabiting the Gulf of Cadiz area (Torres et al, 2017). S. oweniana has the lowest scaling exponent (b = 2.07) in its weight-length relationship among cephalopods inhabiting the study area.…”