RETROSPECTIVE REVIEW OF MORTALITY IN GIANT PACIFIC OCTOPUS (ENTEROCTOPUS DOFLEINI)

Abstract

The giant Pacific octopus (Enteroctopus dofleini) is a popular exhibit species in public display aquaria, but information on health and disease is limited. This retrospective review evaluates time in collection and describes antemortem clinical signs and pathology of giant Pacific octopuses in an aquarium setting. Between March 2004 and December 2013, there were 19 mortalities: eight males, 10 females, and one individual whose sex was not recorded. Average time spent in collection for all octopuses was 375 ± 173 days (males 351 ± 148 days, females 410 ± 196 days). Ten (52.6%) of the octopuses were sexually mature at the time of death, six (31.6%) were not sexually mature, and reproductive status could not be determined in three octopuses (15.8%). Minimal changes were noted on gross necropsy but branchitis was histologically evident in 14 octopuses, often in conjunction with amoeboid or flagellate parasites. Senescence, parasitism, and husbandry were all important contributors to mortality and should be considered when caring for captive octopuses.

The Use of a Species-Specific Health and Welfare Assessment Tool for the Giant Pacific Octopus, Enteroctopus dofleini

“…This study is the first of its kind to have facilities holding E. dofleini document extensive health and welfare assessments, general observations and husbandry practices over an extended period of time. While other studies have used records to retrospectively assess the health of E. dofleini (Seeley et al, 2016), none have documented health changes in real time among multiple facilities. While it is not surprising to most E. dofleini caretakers that changes in feeding behavior and response to stimulus would indicate terminal decline and senescence (Anderson et al, 2002), this is the first study to document a timeline of these behavioral changes associated with senescence and death.…”

“…While we cannot conclude from this study if cephalopods may suffer or experience pain in the same sense that vertebrates do, it is certainly reasonable to assume that injury can compromise the welfare of cephalopods. Even a minor injury can be reflected in morbidity and mortality, such as small fin or mantle abrasions (Hulet, Villoch, Hixon, & Hanlon, 1979;Seeley et al, 2016) and associated bacterial infections (Sherrill, Spelman, Reidel, & Montali, 2000). Therefore, any exposure to injury would implicate a change in the animal's welfare.…”

Behavioral changes in senescent giant Pacific octopus (Enteroctopus dofleini) are associated with peripheral neural degeneration and loss of epithelial tissue

“…Interest in cephalopod models in research is growing (Fiorito et al, 2015) and cephalopods continue to be popular display animals in aquariums, inspiring visitors with their unique anatomy, color changing capabilities and intelligence (Seeley et al, 2016). Most cephalopods are semelparous, meaning they experience a single, terminal reproductive event followed by a period of senescence (Rocha et al, 2001), which is characterized by various behavioral and physiological changes including anorexia, major deterioration of the skin and muscle, sinking of the eyes, stereotypic repetitive behaviors and, occasionally, self-mutilation and autophagy (Anderson et al, 2002;Holst & Miller-Morgan, 2020;Roumbedakis et al, 2018; Z.…”

A retrospective study of pathologic findings in cephalopods (extant subclasses: Coleoidea and Nautiloidea) under laboratory and aquarium management

“…Despite this, the scientific literature documenting spontaneous diseases of cephalopods, particularly in aquaria, is scattered and poorly reviewed with only limited scale retrospective studies having been recorded to date. 26,76,77 This study describes spontaneous disease identified 1186306V ETXXX10.…”