Prospects for captive breeding of poorly known small cetacean species

Abstract

Because of the precarious condition of small cetacean species and subpopulations listed as Endangered or Critically Endangered by the IUCN, use of captive breeding for conservation has been suggested for some of them, and will likely be suggested for others. A successful captive breeding program for a new species cannot be implemented until reliable capture and husbandry techniques have been developed. Techniques for assisted reproduction and reintroduction may also be needed. We review attempts to capture, maintain, and breed poorly known small cetaceans and discuss assisted reproductive technologies (ART) that have been used to enhance captive breeding efforts for other small cetaceans. We conclude that the techniques required for successful captive breeding of most Endangered or Critically Endangered small cetacean species have not been sufficiently developed. Development of these techniques should begin before a species or population is Critically Endangered. In particular, ARTs tend to be species specific, necessitating considerable time, money, and research to develop for each species of concern. Critically Endangered populations cannot afford to lose the individuals needed for technique development. The fairly large captive population sizes necessary (to avoid loss of genetic diversity, inbreeding, and genetic adaptation to captivity), limited space available in aquariums, and high costs of captive breeding and reintroduction programs make it unlikely that captive breeding will play a major role in the conservation of most small cetaceans. The substantive conservation measures needed to prevent extinction of Critically Endangered small cetaceans is reduction or elimination of their primary threats, which are usually by-catch and habitat loss.

A field effort to capture critically endangered vaquitas Phocoena sinus for protection from entanglement in illegal gillnets

“…Captive breeding with subsequent release into the wild has not been used in prior conservation efforts with small cetaceans, despite captive breeding success with some related species (e.g. harbor porpoise Phocoena phocoena, Yangtze finless porpoise Neophocaena asiaeorientalis asiaeorientalis, bottlenose dolphins Tursiops truncatus and T. aduncus; Wang et al 2009, Curry et al 2013. This is due in part to the difficulty with initial acclimation of some cetacean species to human care (e.g.…”

Biological matrices for sampling free‐ranging cetaceans and the implications of their use for reproductive endocrine monitoring

“…Nonsteroidal hormones, such as luteinising hormone and follicle-stimulating hormone, have also been measured in a variety of captive cetaceans (Schneyer et al 1985, Hao et al 2007, Muraco et al 2009); researchers were able to determine a large set of baseline physiological parameters, such as age, length, and weight of males and females at reproductive maturity, seasonality, oestrous cycle, and pregnancy characteristics. Many of these parameters can be used to assess and interpret hormone measurements in capturerelease programmes (Schneyer et al 1985, Curry et al 2013, Schwacke et al 2014.…”

“…Most of these animals are trained to present themselves voluntarily for sample collection, significantly reducing the stress (Laule 2003). Such manipulations can be advantageous from the perspective of applying assisted reproductive technologies in captivity, so that fewer animals are captured to supply private aquaria, and for acquiring baseline information regarding the development of biotechnologies and hormonal therapy that might be used on a population belonging to a threatened species (Robeck et al 1994, Morisaka et al 2010, Curry et al 2013.…”

Uso de gordura subcutânea como matriz biológica na dosagem de esteroides sexuais em baleias jubarte (Megaptera novaeangliae)

“…Moreover, most of these animals are trained to voluntarily present themselves for sample collection, significantly minimizing the stress (LAULE, 2003). Such manipulations can be advantageous from the perspective of applying assisted reproductive technologies in captivity, with fewer animals being captured to supply private aquariums, and acquiring baseline information regarding the development of biotechnologies and hormonal therapy that might be used on a population belonging to a threatened species (MORISAKA et al, 2010;RALLS;BROWNELL, 2013).…”

“…These authors were able to determine a large set of baseline physiological parameters, such as age, length and weight of males and females at reproductive maturity, seasonality, estrous cycle and pregnancy characteristics. Many of these parameters can be used to properly access and interpret hormone measurements in capture-release programs, and vice versa (SCHNEYER; CASTRO;ODELL, 1985;RALLS;BROWNELL, 2013;SCHWACKE et al, 2014).…”