Can Hookpods and reusable LED lights reduce albatross deaths and marine pollution?

Methods

Summary

Hookpods and LED lights will be distributed to three pelagic longline vessels in Brazil (one with enough Hookpods for the entire operation (1200) and  two other vessels will be given 400 each to trial.

Branch lines will be deployed with 45 g Hookpods placed at 2 m from the hook with an un-weighted swivel placed directly above the Hookpod. Chemical light sticks or LED replacements will be attached to branch lines.

  The following variables will be monitored during a minimum of four at sea trips:

i. seabird bycatch (birds / 1,000 hooks);

ii. catch of target and non-target species (fish / 1,000 hooks);

iii. seabird attack rate on baited hooks (attacks / 1,000 hooks);

iv. Hookpod/LED light durability (% lost to breakages);

v. correct use of Hookpods (% correctly deployed);

vi. entanglements of Hookpods with fishing gear (% entangled lines).

Considering the precarious conservation status of great albatrosses, a limit on the number of Diomedea albatross has been set at three birds. If three Diomedea albatross are caught during the experiment, an additional mitigation measure will be added to the control treatment (night setting or bird scaring line use) for all subsequent setting operations for the remainder of the experiment.  

During daylight hours, hooks will be monitored to a maximum distance of approximately 150 m from the vessel stern. For each seabird attack on baited hooks, the species, the distance from the stern, and the mode of attack (surface feed or plunge dive) will be registered. Four types of possibilities will be recorded:

i. successful (the bird retrieved the bait);

ii. unsuccessful (the bird was unable to retrieve the bait);

iii. indeterminate (it was not possible to see the fate of the attack);

iv. capture (the bird is observed to have become hooked).

During night sets, where seabird interactions cannot be recorded, the sink rate of baited hooks will be recorded by attaching pre-programmed CEFAS G5 Time Depth Recorders (TDR) 30 cm from the hook, using electric tape and miniature cable ties. TDRs will be deployed on branch lines, each on the middle (third) hook between buoys.

Pre Analysis Plan

We have two questions to answer from our experiment. 1) How effective is the 45 g Hookpod as a single measure to reduce seabird bycatch in the Brazilian pelagic longline fishery? 2) How effective are LED lights in comparison to single use light sticks, and how readily are they accepted by fishermen?

The analysis of results from monitoring trips will include seasonal seabird abundance by species, seasonal seabird bycatch and attack rates plus seasonal target fish catch rates and a summary of Hookpod/LED lights sink rate data and breakages by issue type. The report will also include a reflection on the levels of acceptance by crew. Results will be prepared in time for the ACAP Sea Bird Working Group meeting, New Zealand 2017.