A novel in situ method for estimation of the carapace length of sheltering spiny lobsters, Panulirus japonicus, via stereo photography

Kawamata, Shigeru; Taino, Seiya

doi:10.1016/j.fishres.2018.01.008

Cited by 1 publication

(3 citation statements)

References 31 publications

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“…Letters “AF” above bar graphs represent sampling immediately after the once‐a‐year fishing in the MPA. The lobster carapace lengths (CLs) were estimated by the noninvasive method of Kawamata and Taino (2018).…”

Section: Resultsmentioning

confidence: 99%

“…Five or six quadrats were sampled at each site. Size frequency distributions of lobsters were also determined three times (at CR2 on 11 November 2015 and AR2 on 19 July 2017 and 25 July 2018) using the noninvasive method of Kawamata and Taino (2018). The method can estimate the CLs by taking photographs of sheltering lobsters using compact stereo cameras (FinePix Real 3D W1 and W3, Fujifilm, Tokyo, Japan).…”

Section: Methodsmentioning

confidence: 99%

“…The method can estimate the CLs by taking photographs of sheltering lobsters using compact stereo cameras (FinePix Real 3D W1 and W3, Fujifilm, Tokyo, Japan). Although the CL in its entirety is generally not visible when lobsters are in their shelters, the method can estimate the CLs accurately (absolute relative errors <10% for 95% of the estimates) when incorporating multiple reference body parts measured from the images, based on predetermined allometric relationships and an algorithm to determine the sex (Kawamata and Taino 2018). In this study, CL estimates were obtained for 61–83% of the observed lobsters including ones visible only by their antennules.…”

Section: Methodsmentioning

confidence: 99%

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Trophic cascade in a marine protected area with artificial reefs: spiny lobster predation mitigates urchin barrens

Kawamata

Taino

2021

Ecological Applications

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An ultimate benefit of marine protected areas (MPAs) is to reverse trophic cascades caused by human‐driven collapse of critical ecological interactions. Here we demonstrate that, despite a small scale (0.28 km2) and not being fully protected, an MPA with strict fishing management and habitat enhancement by artificial reefs (ARs) in southwest Japan can lead to well‐established macroalgal communities on widespread sea urchin barrens through cascading effects of predator recovery. Areas with low urchin densities occurred in and around daytime lobster (Panulirus japonicus) shelters primarily formed by quarry‐rock ARs inside the MPA. We confirmed in the laboratory that lobsters preyed on two dominant sea urchins (Echinometra sp. A and Heliocidaris crassispina), with size‐ and species‐dependent predation. The area with few urchins extended farther (˜65 m) from an AR with numerous lobsters than from a natural shelter (patch reef) with far fewer lobsters. Causation of this pattern was confirmed by a tethering experiment showing that predation on urchins was similarly high at and near lobster shelters but decreased at ˜100 m from the AR to a similar level as at an unprotected site. Time‐lapse photography revealed that predation on tethered urchins was due mostly to the largest size class of lobsters (>100 mm carapace length), which comprised only 7% of the population, highlighting the importance of large‐sized lobsters in controlling urchin abundance in localized areas adjacent to urchin‐dominated barrens. Despite an ongoing once‐a‐year fishing event permitted within the MPA, lobster populations were persistent, demonstrating that the cascading effect of the lobsters on urchins and ultimately macroalgae was robust to temporary reductions in predator population size. Erect macroalgal cover was not simply accounted for by snapshot urchin density or biomass, suggesting a hysteresis effect of the phase shifts between macroalgal dominance and urchin barren states.

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Section: Resultsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

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