The inter‐annual fishing variability in Octopus insularis (Leite & Haimovici 2008) as a result of oceanographic factors

Abstract

Octopus insularis, despite being widely fished from Brazil to Mexico, has only recently been described as a different species from the sympatric Octopus vulgaris complex in the tropical Atlantic, where its occurrence is determined by different environmental factors. Using a 10‐year time series from Brazil, we modeled how topographic aspects and oceanographic variables affected the landings of O. insularis. For that we used a locally weighted scatterplot smoothing (LOESS) technique and residual autocovariate‐boosted regression trees (RAC‐BRTs). In addition to the octopus landing per unit effort (LPUE) being driven by the seafloor structure, we also observed that it was directly related to the temperature and inversely related to chlorophyll. Higher LPUEs were observed in warmer years. Although the relationship between LPUE and chlorophyll or temperature has not yet been explained under laboratorial conditions, the higher catches observed at higher temperatures may be both a result of the local fishing dynamics and a warning toward the possibility of future niche expansion, due to climate change. If the latter is confirmed, octopus fisheries in parts of the South Atlantic would need to adapt to a smaller, and thus cheaper, body‐sized species.

Assessing Negative Welfare Measures for Wild Invertebrates: The Case for Octopuses

“…These conditions facilitate behavioral studies by allowing individuals to be tracked closely and continuously using cameras placed in front of their dens or in focal follows during excursions from the den [54]. Most of the media we collected were recorded by or during interactions with fishermen, reflecting the fact that O. insularis is a highly fished species in Brazil [14,29] and that these animals regularly interact with fishermen in many Brazilian coastal areas. Nevertheless, to date, no study has attempted to understand the impacts of capture and handling by fishermen on free-living octopuses.…”

“…Wild octopuses must constantly weigh the benefit of foraging against the cost of defense and the threat of predation [8] and interactions with other animals [9,10] and must select suitable shelters and perform regular maintenance on this den [11]. Lethal and sublethal predation, fishing, and agonistic and interspecific interactions are some of the daily challenges that can affect the welfare of octopuses [12][13][14], resulting in physical damage, stress, and/or pain [4].…”

Ficha de Octopus insularis

“…Octopus insularis sustenta a pesca de subsistência artesanal no Nordeste do Brasil (Lopes et al, 2021). Suas principais ameaças são as práticas de pesca ilegal (principalmente de juvenis nas áreas rasas costeiras) sem manejo e o uso de água sanitária na pescaria, que ocasiona a destruição do habitat em que vive,principalmente suas áreas de berçário, localizadas em regiões mais rasas, além da ação antrópica sobre os ambientes recifais Freitas et al, 2022).…”

Octospy: What Octopus insularis do in their dens

“…It can be found on hard substrates, particularly reefs, rubble, and bedrock, where it inhabits natural holes and crevices (dens) and is a predator of benthic invertebrates (Leite, et al, 2009, b). O. insularis has long been a significant component of Brazilian and Mexican fisheries (Flores‐Valle et al, 2018; Gonzalez‐Gomez et al, 2020; González‐Gómez et al, 2018; Leite et al, 2008; Lima et al, 2017; Lopes et al, 2021) and it co‐occurs with at least seven other species of octopus throughout its geographic range (Avendaño, Roura, et al, 2020; Hanlon, 1988; Jereb et al, 2014; Jesus et al, 2021; Leite & Haimovici, 2006). Due to a proclivity for warm (23°C and 30°C) shallow (0.5–40 m) water (Leite et al, 2008; Leite, Haimovici, Mather, & Oliveira, 2009; Rosas‐Luis et al, 2020), its high abundance (Batista & Leite, 2016; Bouth et al, 2011), and its tendency to scatter highly visible prey debris in the vicinity of its den (Leite et al, 2016; Mather., 1991), O. insularis are relatively easy to locate and observe, making it an ideal species in which to study behavior in the wild.…”