STABLE ISOTOPES ANALYSIS ON BALEEN WHALES (SUBORDER: MYSTICETI): A REVIEW UNTIL 2017
DOI:
https://doi.org/10.18764/1981-6421e2020.10Keywords:
Baleen whales, Mysticeti, Stable Isotopes Analysis, Conservation EcologyAbstract
ABSTRACT
Stable Isotope Analysis (SIA) has provided information on ocean productivity, and ecological aspects related to whales’ habitat use and feeding ecology, stock structure, physiology, and evolution. We reviewed published studies using SIA on whales worldwide from November 1979 to June 2017. Gaps in geographical areas and heterogeneity amongst species studied using this methodology were
assessed. We also investigated which tissue was most frequently analysed, sources of variation in stable isotope values, how this methodology has been combined with other techniques, and how it can be useful for the conservation of the taxon and marine ecosystems. A total of 63 publications were found, and it was possible to detect a general increase in the number of publications along time, as 49% of the studies were from the last 7.5 years of the period analyzed. Almost 55% of studies focused on foraging ecology and habitat use. The baleen plate was the main tissue analyzed. Studies were related to 14 species, the most common being the fi n whale, Balaenoptera physalus (N=19) and the bowhead whale, Balaena mysticetus (N=18). Telemetry and SIA methodologies combined were helpful to understand geographical variations in stable isotope values. The methodology can also be valuable under the current scenario of climate change, for example providing information on feeding plasticity and changes in niche amplitude of diff erent species. Despite uncertainties related with stable isotopes distribution in the ocean, and with its incorporation rates for whales, for example, SIA provides primordial ecological information for effi cient management and conservation of this group.
RESUMO
A análise de isótopos estáveis (AIE) fornece informações sobre a produtividade do oceano e aspectos ecológicos de baleias relacionados ao uso do habitat e ecologia alimentar, estrutura de estoque, fi siologia e evolução. Foram revisados estudos publicados usando a AIE em baleias em todo o mundo entre novembro de 1979 e junho de 2017. Foram avaliadas lacunas nas áreas geográfi cas e
heterogeneidade entre as espécies estudadas usando essa metodologia. Também investigamos quais tecidos foram mais utilizados para análise, as fontes de variação em valores de isótopos estáveis, a combinação desta metodologia com outras técnicas e como pode ser útil para a conservação deste táxon e dos ecossistemas marinhos. Um total de 63 publicações foi encontrado e foi possível detectar aumento no número de publicações, uma vez que 49% dos estudos foram realizados nos últimos 7 anos e meio do período analisado. Quase 55% dos estudos concentraram-se na ecologia de forrageio e no uso do habitat. As cerdas bucais foram o principal tecido analisado. Os estudos investigaram
14 espécies, sendo mais comuns aqueles relacionados a baleia-fi n, Balaenoptera physalus (N=19) e a baleia-da-Groenlândia, Balaena mysticetus (N=18). As metodologias de telemetria e AIE combinadas foram úteis para entender as variações geográfi cas em valores de isótopos estáveis. A
metodologia pode também ter valor no cenário de mudanças climáticas fornecendo informações sobre plasticidade alimentar e amplitude de nicho de diferentes espécies, por exemplo. Apesar das incertezas relacionadas à distribuição dos valores de isótopos estáveis no mar e às taxas de
incorporação em baleias, por exemplo, a AIE fornece informações ecológicas primordiais para o manejo e conservação desse grupo.
Palavras-chave: Balaenopteridae; Balaenidae; Análise de isótopos estáveis; Ecologia da conservação.
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