A Wandering Albatross lands behind a fishing vessel; artwork by Maureen Bennetts, after a photograph by Dimas Gianuca

Can Zhou (Texas A&M University, College Station, USA) and Nigel Brothers have published in the journal Bird Conservation International on assessing bycatch in pelagic longline fisheries by recording seabird interactions.

The paper’s abstract follows:

“The incidental mortality of seabirds in fisheries remains a serious global concern. Obtaining unbiased and accurate estimates of bycatch rates is a priority for seabird bycatch mitigation and demographic research. For measuring the capture risk of seabird interactions in fisheries, the rate of carcass retrieval from hauled gear is commonly used. However, reliability can be limited by a lack of direct capture observations and the substantial pre-haul bycatch losses known to occur, meaning incidence of seabird bycatch is underestimated. To solve this problem, a new measure (bycatch vulnerability) that links an observed interaction directly to the underlying capture event is proposed to represent the capture risk of fishery interactions by seabirds. The new measure is not affected by subsequent bycatch loss. To illustrate how to estimate and analyse bycatch vulnerability, a case study based on a long-term dataset of seabird interactions and capture confirmation is provided. Bayesian modelling and hypothesis testing were conducted to identify important bycatch risk factors. Competition was found to play a central role in determining seabird bycatch vulnerability. More competitive environments were riskier for seabirds, and larger and thus more competitive species were more at risk than smaller sized and less competitive species. Species foraging behaviour also played a role. On the other hand, no additional effect of physical oceanic condition and spatio-temporal factors on bycatch vulnerability was detected. Bycatch vulnerability is recommended as a replacement for the commonly used bycatch rate or carcass retrieval rate to measure the capture risk of an interaction. Combined with a normalized contact rate, bycatch vulnerability offers an unbiased estimate of seabird bycatch rate in pelagic longline fisheries.”

Read a related paper by the same authors.

With thanks to Nigel Brothers.

Reference:

Zhou, C. & Brothers, N. 2021.  Seabird bycatch vulnerability in pelagic longline fisheries based on modelling of a long-term dataset.  Bird Conservation International  doi.org/10.1017/S0959270921000046.

https://www.tamu.edu/John Cooper, ACAP Information Officer, 13 March 2021

Whenua Hou Diving Petrel 

Johannes Fischer (School of Biological Sciences, Victoria University of Wellington, New Zealand) and colleagues have published in the journal Marine Progress Report Series on at-sea activities of the Critically Endangered (and recently described) Whenua Hou Diving Petrel Pelecanoides whenuahouensis that breeds only on predator-free Codfish Island (Whenua Hou), New Zealand.

The paper’s abstract follows:

“Without insights into the threats affecting species across their distributions and throughout their annual cycles, effective conservation management cannot be applied. The Whenua Hou diving petrel Pelecanoides whenuahouensis (WHDP) is a Critically Endangered small seabird whose offshore habits and threats are poorly understood. We tracked WHDPs year-round in 2015/16, 2017/18, and 2018/19 using global location-sensing immersion loggers to identify offshore distribution, movements, behaviour, and overlap with commercial fishing effort. During the breeding period, WHDPs ranged from southern Aotearoa (New Zealand) to Maukahuka (Auckland Islands). After breeding, WHDPs migrated southwest towards the Polar Front south of Australia, exhibited clockwise movements, and returned to their breeding grounds via the Subantarctic Front. During the non-breeding period, WHDPs exhibited extreme aquatic behaviour and spent >95% of their time on, or under, water. The core areas used consistently during breeding and non-breeding periods warrant listing as Important Bird and Biodiversity Areas. Spatiotemporal overlap of commercial fishing effort with breeding distributions was considerable, in contrast with non-breeding distributions. Spatiotemporal management of anthropogenic activity around the breeding colony during the breeding period could help protect WHDPs, but such measures should be subjected to a structured decision-making framework. Our results illustrate the importance of year-round studies to inform conservation of marine species.”

Follow research conducted on the Whenua Hou Diving Petrel on the Flying Penguin Force Facebook page.

Reference:

Fischer, J.H., Debski, I., Spitz, D.B., Taylor, G.A. &. Wittmer, H.U. 2021.  Year-round offshore distribution, behaviour, and overlap with commercial fisheries of a Critically Endangered small petrel.  Marine Progress Report Series 660: 171-187.

John Cooper, ACAP Information Officer, 12 March 2021

UPDATE:  The Pelagic Australis arrived at Gough Island on 10 March after a nine-day voyage from Cape Town and safely landed its members of the GIRP team ashore.

The Pelagic Australis about to leave Cape Town Harbour for Gough Island with the second GIRP team aboard, Chris Jones and Michelle Risi centre, Peter Ryan right; photograph by the RSPB

A second sailing of the Pelagic Australis that left Cape Town yesterday for Gough Island follows the first of last month with more team members of the United Kingdom’s Gough Island Restoration Programme (GIRP) aboard, following two weeks of quarantine to ensure their being COVID-19 free.  GIRP aims to eradicate the island’s House Mice that have taken to attacking and killing breeding albatrosses and petrels, including the Critically Endangered and near-endemic Tristan Albatross Diomedea dabbenena.  Along with members of GIRP aboard the yacht is Peter Ryan, Director of the University of Cape Town’s FitzPatrick Institute of African Ornithology.  Peter is an old Gough Island hand having first visited the island to conduct research on the impact of plastic ingestion on Great Shearwaters Ardenna gravis towards his MSc (along with ACAP’s Information Officer) way back in 1984.  With him on the yacht is his erstwhile postgraduate student Chris Jones, who graduated with an MSc in 2018 following a study of Gough’s prions Pachyptila spp. Also aboard is Michelle Risi, a member of ACAP’s World Albatross Day Group (and designer of the ‘WAD2021’ suite of posters of Critically Endangered albatrosses).  Michelle has already spent three tours of service on Gough working for GIRP monitoring the island’s seabirds – two of them consecutive years – along with husband, Chris Jones.

From left: Vonica Perold, Roelf Daling, Kim Stevens, Michelle Risi, Alexis Osborne and Chris Jones on Gough Island in 2020

When they arrive on the island they will meet up with GIRP member Alexis Osborne, who sailed last month with the first team.  Alexis is another of Peter’s past MSc students, having graduated in 2020 for a study of moult in allbatrosses and giant petrels that included information collected on Gough.  And already on the island since last year are two more of Peter’s students, Vonica Perold and Kim Stevens, both working towards their PhDs.  With no less than five marine ornithologists linked to the ‘Fitztitute’ together on the island later this month ACAP Latest News is sensing a photo opportunity!

Kim Stevens (left) and Von Perold weigh Subantarctic Fur Seal Arctocephalus tropicalis pups on Gough Island, photograph by Roelf Daling

A blast from the past: a young (and exuberant) Peter Ryan (left) with colleagues on Gough Island in 1984.  ACAP’s Information Officer is on the right; in between them are Barry Watkins, Stevi Broni and the late Jim Enticott

With thanks to Michelle Risi, Peter Ryan and Antje Steinfurth.

John Cooper, ACAP Information Officer, 03 March 2021, updated 11 March 2021

Black-browed Albatrosses accumulate behind a fishing vessel in the South Atlantic

Can Zhou (Texas A&M University, College Station, USA) and Nigel Brothers have published in the ICES Journal of Marine Science on assessing seabird bycatch by observing pre-capture interactions from pelagic longline fishing vessels.

The paper’s abstract follows:

“Fishery bycatch poses a serious threat to seabird populations globally. Traditional haul-only post-capture observations are inadequate and inefficient to document seabird bycatch due to the substantial bycatch loss known to occur. Pre-capture observations offer an alternative by documenting seabird interactions leading up to captures. Based on the long-term large-scale dedicated field observations, this study revealed significant risk factors for the pre-capture stages of the seabird bycatch process in pelagic longline fisheries using Bayesian methods. Rough sea conditions were found to correlate with more seabirds following fishing vessels. Species identity, density effect, inter-species effect, and sea condition were found to significantly affect how frequently seabirds aggregated around a fishing vessel engage in bait-taking interactions. Intra-species competition was found to be the dominant type of density effect. Moreover, a web of inter-species interactions was identified to facilitate the bait-taking of superior competitors at the expense of inferior ones. The findings of this study are relevant to fishery managers in updating current data collection protocols to alleviate data issues caused by bycatch loss, to conservation biologists in quantifying bycatch risks for susceptible seabird populations, and in aiding the design and evaluation of bycatch mitigation measures.”

With thanks to Nigel Brothers.

Reference:

Zhou, C. & Brothers, N. 2021.  Interaction frequency of seabirds with longline fisheries: risk factors and implications for management.  ICES Journal of Marine Science doi.org/10.1093/icesjms/fsab014.

John Cooper, ACAP Information Officer, 11 March 2021