Size at maturity and length-weight relationships of the blurred lantern shark Etmopterus bigelowi (Squaliformes: Etmopteridae) caught off southeastern Brazil

The blurred lantern shark Etmopterus bigelowi, a deep-water squaloid shark, is globally widespread in temperate and tropical waters, but there is little available information about its biology owing to its relative rarity of capture and taxonomic confusion with its sibling species Etmopterus pusillus. Specimens used in this study were collected from July to December 2004 as by-catch in the commercial deepwater trawl fishery targeting red shrimp Aristaeomorpha foliacea in the southwestern Atlantic. We examined 55 specimens (22 males and 33 females) ranging in total length (TL) from 31.5 to 73 cm and in total weight from 103 to 1600 g. Length-weight relationships were explored for each sex and significant differences were found in the slope coefficients of the male and female regressions. The size at maturity for each sex was evaluated fitting a logistic regression. Females matured at larger sizes than males, with estimated sizes at first maturity of 56.0 cm TL for females and 45.1 cm TL for males. The present study provides important preliminary information about E. bigelowi that can be incorporated in risk assessment and stock assessment models, essential for efficient management practices aimed at avoiding overexploitation of these vulnerable deep-sea sharks.

Age and growth of bluemouth, Helicolenus dactylopterus (Delaroche, 1809) from the Azores

The age and growth of the Helicolenus dactylopterus (Delaroche, 1809) in the Azorean waters were studied using whole and sliced otolith readings. Individuals were collected during demersal surveys carried out around the Azores islands and its most important fishing banks and also from commercial landings. A total of 1024 individuals were measured, weighed and their sex was determined. Individuals ranged from 3 to 49 cm total length (TL) and their estimated ages between 0 and 32 years old. The otoliths showed the typical teleost fish pattern with alternated opaque and hyaline rings. Significant differences between sliced and whole otolith readings were found, especially after 7 years old (>25 cm TL). Sliced otoliths were found easier to read, regardless of TL or age. Comparisons with other studies for the Azores region and other areas are discussed.