A breeding Grey-headed Albatross on Australia’s Macquarie Island, now free of introduced vertebrates following several successful eradication efforts; photograph by Melanie Wells

Dena Spatz (Pacific Rim Conservation, Honolulu, Hawaii, USA) and colleagues have published open access in the journal Scientific Reports on a synthesis of 1550 eradication attempts of introduced vertebrates on 998 islands.

The paper’s abstract follows:

“Islands are global hotspots for biodiversity and extinction, representing ~ 5% of Earth’s land area alongside 40% of globally threatened vertebrates and 61% of global extinctions since the 1500s. Invasive species are the primary driver of native biodiversity loss on islands, though eradication of invasive species from islands has been effective at halting or reversing these trends. A global compendium of this conservation tool is essential for scaling best-practices and enabling innovations to maximize biodiversity outcomes. Here, we synthesize over 100 years of invasive vertebrate eradications from islands, comprising 1550 eradication attempts on 998 islands, with an 88% success rate. We show a significant growth in eradication activity since the 1980s, primarily driven by rodent eradications. The annual number of eradications on islands peaked in the mid-2000s, but the annual area treated continues to rise dramatically. This trend reflects increases in removal efficacy and project complexity, generating increased conservation gains. Our synthesis demonstrates the collective contribution of national interventions towards global biodiversity outcomes. Further investment in invasive vertebrate eradications from islands will expand biodiversity conservation while strengthening biodiversity resilience to climate change and creating co-benefits for human societies.”

Read a popular account of the publication here.

Reference:

Spatz, D.R., Holmes, N.D., Will, D.J., Hein, S., Carter, Z.T., Fewster,  R.M., Keitt, B., Genovesi, P., Samaniego, A., Croll, D.A., Tershy, B.R. & Russell, J.C. 2022.  The global contribution of invasive vertebrate eradication as a key island restoration tool.  Scientific Reports 12, 13391.  doi.org/10.1038/s41598-022-14982-5.

John Cooper, ACAP News Correspondent, 16 August 2022

A Campbell Albatross off North Cape, New Zealand; photograph by Kirk Zufelt

A report prepared by Vita Maris for New Zealand’s Department of Conservation titled, BCBC2020-11b: Development of bottom longline underwater setting devices, has been released by the Conservation Services Programme. 

Noting ACAP best practice guidelines on bottom long-line fishing which include the three mitigation measures of: night setting, line weighting, and tori lines, the authors signal advantages of underwater setters, including: reduced risk to birds, increased sink rates, and the potential of daytime setting for fishers.

The summary as follows:

“Estimated capture rates of at-risk seabirds by the small vessel demersal longline fleet are likely to be acceptable in the long term; both scientifically (e.g., Richard et al. 2017), and from a social ‘licence to operate’ perspective (e.g., RNZ, 2020), indicating the need for improvements in performance over and above that achievable using traditional mitigation measures.

The Agreement for the Conservation of Albatrosses and Petrels (ACAP) best practice guidance for bottom longline fishing includes use of the following three measures at all times: night setting, line weighting, and tori lines (ACAP, 2019). Setting lines for the ‘bite time’ over the change of light means many sets targeting snapper in the summer months do not meet the ACAP definition of best practice (Pierre et al., 2018). Additionally, the ACAP advice recognises that night setting may not be effective in bright moonlight, or for crepuscular/nocturnal foragers, and notes that mitigation measures need to be acceptable to fishers and not affect fish catch rates. Similarly, tori lines are often not fully effective to the prescribed aerial extent (pers. obs. DG).

The introduction of mitigation standards for demersal longliners (MPI, 2019) and subsequent changes to regulation (MPI 2021) require a hook depth of 5 m at the end of the tori line aerial extent, and likely require substantial changes to gear configuration and setting speed for some of the fleet (Goad & Olsen, 2022).

Underwater setting has the potential to increase sink rates and reduce risk to birds. It is particularly relevant to meeting the latest regulations and mitigation standards, whilst maintaining flexibility of gear configuration for fishers. It also has the potential to open up daytime setting in high-risk times and places.

Efforts to reduce the availability of pelagic longline hooks to birds has focused on increasing the sink rate of the hook, either mechanically (Gilman et al., 2003, Ryan & Watkins 2002, Robertson & Ashworth 2010), or by adding weight (e.g. Robertson 2013), or protecting the barb of the hook (Oceansmart, 2011, Hookpod, 2020). These ‘hook by hook’ approaches are feasible for pelagic longlines where branch lines are longer than 10 m, baited as they are set, set relatively slowly (e.g. Robertson 2013, Goad et al., 2019), and the hook sinks, certainly initially, independently from the mainline (Robertson et al., 2010).

Conversely, the inshore manual baiting demersal longline fleet in New Zealand clip on pre-baited hooks with short branchlines (or snoods), typically 0.6 m length, to a stoppered mainline relatively quickly (Goad et al., 2010). Therefore, in order to set demersal longlines underwater, both the hook and the mainline have to be deployed at depth. This presents a different set of challenges, and a downward force must be applied to the mainline in order to achieve sufficient depth.

This report describes work undertaken developing two underwater setting devices. The first was initially conceived by Dave Kellian, and is described here as the ‘underwater setter’. It is towed behind the vessel at depth and the longline passes under a guide. Previous work is described in Goad, 2011; Baker et al., 2013; 2016; and Goad et al., 2020. The second device was conceived by Nigel Hollands and uses a roller held under the surface by a pole fixed to the vessel, with the longline passing under the roller. It is described here as the ‘line depressor’ and previous work is described in Hollands et al., 2022.”

Reference:

Goad, D., Kiddie, B., Hollands, N., Clow, A., Angel, J. 2022. Development of bottom longline underwater setting devices. BCBC2020-11b final report prepared by Vita Maris for Department of Conservation, Wellington. 30 pp.

Posted 15 August 2022

Applications are open for ACAP’s 2022 Secondment Programme. Proposals should clearly address tasks contained within the work programmes of the Advisory Committee (see Annex 4, MoP7 Report) and Secretariat (see Annex 2, MoP7 Report), and aspire to foster capacity-building within Parties. Applicants are encouraged to develop proposals that account for any ongoing practical challenges and limitations associated with the COVID-19 pandemic.

Progress reports from previous secondments can be found at the ACAP website.

Applications will only be accepted from ACAP Parties.  Applicants are encouraged to contact the Working Group Convenors, the Advisory Committee Chair or Vice-chair, or the This email address is being protected from spambots. You need JavaScript enabled to view it. to help identify ACAP priority areas for their proposal.  Completed applications are to be submitted to relevant ACAP National Contact Points, who will then forward them to the ACAP Secretariat.

Applications must be received by the ACAP Secretariat by close of business on Monday, 26 September 2022. Applicants will be advised of the outcome of their application by Tuesday, 8 November 2022.

Click here for more information, including application criteria, and the application form.  Also available in French and Spanish.

12 August 2022

 
Wandering Albatross at sunset, Île de la Possession, Crozet Islands; photograph by Franck Theron

Ruijiao Sun (Biology Department, Woods Hole Oceanographic Institution, Massachusetts, USA) and colleagues have published open access in the journal Ecological Monographs on life-history outcomes of a male-skewed population of Vulnerable Wandering Albatrosses Diomedea exulans on Île de la Possession, Crozet Islands, caused by fishery bycatch.

The paper’s abstract follows:

“Many animals form long-term monogamous pair bonds, and the disruption of a pair bond (through either divorce or widowhood) can have significant consequences for individual vital rates (survival, breeding, and breeding success probabilities) and life-history outcomes (lifetime reproductive success [LRS], life expectancy). Here, we investigated the causes and consequences of pair-bond disruption in wandering albatross (Diomedea exulans). State-of-the-art statistical and mathematical approaches were developed to estimate divorce and widowhood rates and their impacts on vital rates and life-history outcomes. In this population, females incur a higher mortality rate due to incidental fishery bycatch, so the population is male-skewed. Therefore, we first posited that males would show higher widowhood rates negatively correlated with fishing effort and females would have higher divorce rates because they have more mating opportunities. Furthermore, we expected that divorce could be an adaptive strategy, whereby individuals improved breeding success by breeding with a new partner of better quality. Finally, we posited that pair-bond disruptions could reduce survival and breeding probabilities owing to the cost of remating processes, with important consequences for life-history outcomes. As expected, we showed that males had higher widowhood rates than females and females had higher divorce rates in this male-skewed population. However, no correlation was found between fishing effort and male widowhood. Secondly, contrary to our expectation, we found that divorce was likely nonadaptive in this population. We propose that divorce in this population is caused by an intruder who outcompetes the original partner in line with the so-called forced divorce hypothesis. Furthermore, we found a 16.7% and 18.0% reduction in LRS only for divorced and widowed males, respectively, owing to missing breeding seasons after a pair-bond disruption. Finally, we found that divorced individuals were more likely to divorce again, but whether this is related to specific individual characteristics remains an important area of investigation.”

Reference:

Sun, R., Barbraud, C., Weimerskirch, H., Delord, K., Patrick, S.C., Caswell, H. & Jenouvrier, S. 2022.  Causes and consequences of pair-bond disruption in a sex-skewed population of a long-lived monogamous seabird.  Ecological Monographs  doi.org/10.1002/ecm.1522.

John Cooper, ACAP News Correspondent, 11 August 2022