Biological and ecological traits of Bathynomus giganteus and Bathynomus miyarei (Crustacea: Isopoda): Contribution to the conservation of deep‐sea in southern Brazil

Biological and ecological traits of Bathynomus giganteus and Bathynomus miyarei (Crustacea: Isopoda): Contribution to the conservation of deep‐sea in southern Brazil

This study aimed to determine biological and distributional aspects of deep‐sea giant isopods Bathynomus giganteus and Bathynomus miyarei to assess their extinction risk. Bathynomus giganteus (663 specimens) and B. miyarei (649 specimens) were collected during five research cruises involving 265 h o...

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Bibliographic Details
Published in:Aquatic conservation Vol. 31; no. 8; pp. 2084 - 2094
Main Authors: Boos, Harry, Scalco, Allan Cesar Silva, Araujo, Paula Beatriz
Format: Journal Article
Language:English
Published: Oxford Wiley Subscription Services, Inc 01-08-2021
Subjects:
Animals
Aquatic crustaceans
Bathynomus giganteus
Bathynomus miyarei
bycatch
Cruises
deep‐sea
Depth
Evaluation
Females
Fishing
giant isopods
growth
Isopoda
IUCN Red List
Longevity
Males
marine conservation
Risk assessment
Sex ratio
Sexual maturity
Species extinction
Vertical distribution
Brazil
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Summary:This study aimed to determine biological and distributional aspects of deep‐sea giant isopods Bathynomus giganteus and Bathynomus miyarei to assess their extinction risk. Bathynomus giganteus (663 specimens) and B. miyarei (649 specimens) were collected during five research cruises involving 265 h of sampling effort during 32 fishing operations of circular pots, baited traps, ranging from 400 and 1,000 m deep, between 26 and 29°S adjacent to the Brazilian coast. A trend towards larger, sexually mature animals in shallower regions was observed for both species, and depth was the most important environmental variable influencing the animals’ distribution. Bathynomus giganteus were collected between 600 m and 1,000 m depth, while the highest densities of B. miyarei were at shallower depths, between 400 and 600 m. The sex ratio was equal for both B. giganteus and B. miyarei for different seasons, latitudes and bathymetries. The sexual maturity of B. giganteus was estimated at 340–345 mm total length for males and between 280–290 mm for females. Bathynomus miyarei males’ sexual maturity was estimated in the 225–230 mm size class. Bathynomus giganteus showed reproductive activity throughout the year. The longevity of B. giganteus was estimated at 6 years for males and 7.7 years for females. The longevity of B. miyarei was estimated at 9 years for males and 6 years for females. Extinction risk assessment for B. giganteus, which has a greater latitudinal and bathymetric distribution, was evaluated as Least Concern. However, B. miyarei was evaluated in the Data Deficient category.
ISSN:1052-7613
1099-0755
DOI:10.1002/aqc.3583