Study

Movement, depth distribution and survival of spinetail devilrays (Mobula japanica) tagged and released from purse-seine catches in New Zealand

  • Published source details Francis M.P. & Jones E.G. (2017) Movement, depth distribution and survival of spinetail devilrays (Mobula japanica) tagged and released from purse-seine catches in New Zealand. Aquatic Conservation: Marine and Freshwater Ecosystems, 27, 219-236.

Actions

This study is summarised as evidence for the following.

Action Category

Release protected or species of concern alive after capture

Action Link 		Marine Fish Conservation
  1. Release protected or species of concern alive after capture

    A replicated study in 2013–2015 in coastal pelagic waters of the Tasman Sea, off northern New Zealand (Francis & Jones 2017) found that some individuals of the protected and endangered spinetail devilray Mobula japonica survived release after accidental capture in purse-seine nets and normal handling practices, but survival was decreased in rays brought aboard entangled in the net. Three of seven data tagged devilrays survived capture and release, two over monitoring lengths of 30 days and one with a monitoring length of 82 days. Four rays died within 1–2 days of release, indicated by rapid descents in the data to ~1,800 m. All three rays that survived had been brought onboard from the purse-seine in a convey net, or brailer, and released directly from the convey net or using a rope and winch. All rays that died had been entangled in a part of the net (bunt) and hauled onboard in the final section of the main purse-seine net. Rays were tagged by observers aboard commercial skipjack purse-seine vessels after being lifted on deck. Only rays hauled onboard were tagged as those released whilst in the water were all expected to survive. Satellite-archival tags were anchored in the central part of the wing musculature using an umbrella anchor with eight plastic barbs. Anchors were attached to tags by 10-11 cm monofilament nylon or stainless-steel tethers. Tags were secondarily attached to the wing with a numbered conventional plastic tag and had a release device that triggered at 1,700–1,800 m.

    (Summarised by: Leo Clarke)

Output references
What Works 2021 cover

What Works in Conservation

What Works in Conservation provides expert assessments of the effectiveness of actions, based on summarised evidence, in synopses. Subjects covered so far include amphibians, birds, mammals, forests, peatland and control of freshwater invasive species. More are in progress.

More about What Works in Conservation

Download free PDF or purchase
The Conservation Evidence Journal

The Conservation Evidence Journal

An online, free to publish in, open-access journal publishing results from research and projects that test the effectiveness of conservation actions.

Read the latest volume: Volume 21

Go to the CE Journal

Discover more on our blog

Our blog contains the latest news and updates from the Conservation Evidence team, the Conservation Evidence Journal, and our global partners in evidence-based conservation.

Who uses Conservation Evidence?

Meet some of the evidence champions

Endangered Landscape ProgrammeRed List Champion - Arc Kent Wildlife Trust The Rufford Foundation Save the Frogs - Ghana Mauritian Wildlife Supporting Conservation Leaders
Sustainability Dashboard National Biodiversity Network Frog Life The international journey of Conservation - Oryx Cool Farm Alliance UNEP AWFA Bat Conservation InternationalPeople trust for endangered species Vincet Wildlife Trust
For a full list of, and information about, our champions:
All Evidence Champions
About our champions, why and how to become one:
Become an Evidence Champion

This website uses Cookies

We use limited Cookies to run the site and to analyse our traffic (none for site vendors). By using this site, you will be providing your consent to our use of Cookies.

Accept & continue