uGear configuration on a New Zealand Snapper longliner; from the publication

The Conservation Services Programme (CSP) of New Zealand’s Department of Conservation works to reduce the impact of commercial fishing on protected species in New Zealand fisheries waters. Here is one of its most recent final reports.

The report’s summary follows:

“The introduction of mitigation standards for demersal longliners (MPI, 2019) and subsequent changes to regulation (MPI, 2021) have resulted in increased attention on sink times to depth and the depth of hooks at the end of the aerial extent of tori lines. Previous work has shown that sink times to depth vary with gear setup and position on line, as well as with environmental conditions (Goad et al., 2010; Goad, 2011; Pierre et al., 2013). However, for a given gear setup, times to depth for the slowest sinking part of the line show much less variation within and between sets (Goad, 2021).

The snapper-target demersal longline fleet deploy pre-baited hooks typically on 60 cm snoods. Hooks are stored on cards, usually containing 50 or 60 hooks and are clipped onto the longline during the set, separated by twine stoppers which are regularly spaced along a monofilament nylon backbone. The fleet employs a range of gear setups, and many vessels have faster-sinking variations for use at high-risk times. However, most vessels generally have no accurate measure of depth at the end of the tori line for different gear configurations, and limited time to experiment with variations to gear setup and tori line design to improve depths at the end of the aerial extent.

With a shift towards an outcome-based approach to regulating line weighting it is necessary to better understand sink times to depth for different gear configurations, and to communicate to fishers the options available to meet the prescribed depth at the end of the tori line.”

Reference:

Goad, D. & Olsen Z. 2022.  Measuring sink rates of a range of line weighting configurations in the snapper longline fishery.  BCBC2021-03 final report prepared by Vita Maris for the New Zealand Department of Conservation, Wellington.  18 pp.

John Cooper, ACAP Information Officer, 05 May 2022

 
Waved Albatross at sea, a species that occurs in Peruvian waters

Joanna Alfaro of the Peruvian NGO ProDelphinus writes to ACAP Latest News:  “It is my pleasure to share with you a guide on safe handling and release of Endangered, Threatened and Protected (ETP) species for purse seine fisheries; our small contribution for marine conservation and sustainable fisheries.  It was a pleasure to work on this document with the team in ProDelphinus and several fishers who shared their traditional knowledge for this guide.  The guide has already been launched at a meeting with over 300 purse seine fishers, and we hope to continue sharing it with more fishers.”

Mi post es para compartirles un documento que ame pues es un granito de arena a la conservacion marina y las pesquerias sostenibles, pero tb por que estuvimos en esto junto con un equipo maravilloso en Pro Delphinus. Calientita les dejo la Guia de Liberacion y Manipulacion de Fauna Marina en cerco pesquero. Se agradece de antemano las descargas y compartidas.

La guia le presentamos ante 300 pescadores industriales de cerco, esperamos poder seguir presentandola.

With thanks to Joanna Alfaro Shigueto. ProDelphinus, Peru.

John Cooper, ACAP Information Officer, 04 May 2022

“Example of visual review process for Steeple Jason “Bubble” area Black-browed Albatross detections at a zoom level of 1:75.  Each grid is 10 × 10 m”; from Hayes et al. 2021

The Wildlife Conservation Society (WCS), Duke University and the University of Tennessee – Knoxville are working together to adapt and train a convolutional neural network (CNN) to detect a wide range of species in variable environments.  The following edited appeal has been received from Wieteke Holzhuizen, Pacific Seabird Group.

“For decades, WCS researchers travelled to two remote islands on the Falkland Islands (Islas Malvinas)* to conduct ground surveys of the largest Black-browed Albatross Thalassarche melanophris colony in the world.  Due to the large size of the colony and steep terrain, researchers would spend weeks counting and extrapolating data from sample transects to estimate population size.  In recent years, we have started to use an off-the-shelf Phantom 4 Pro quadcopter to design island-wide surveys and collect high-resolution imagery data that can be replicated each year.  Furthermore, WCS partnered with researchers from the Duke University Marine Robotics and Remote Sensing Lab to develop a deep-learning algorithm trained to detect nesting albatrosses with a computer model accuracy of 97%.  This level of accuracy, coupled with the ability to easily replicate pre-programmed flights, presents a much easier, more accurate and more consistent way to document population growth or decline in colonial nesting seabirds.

Black-browed Albatross colonies on Grand Jason (left) and Steeple Jason; photographs by Ian Strange and Robin Woods

WCS and Duke University have recently partnered on a drone-based survey of Black-browed Albatrosses and Southern Rockhopper Penguins Eudyptes chrysocome on Grand Jason and Steeple Jason Islands in the Falkland Islands (Islas Malvinas)*.  Using data from 12 drone surveys flown by WCS researchers across two years, (avg. resolution: five cm/pixel in 2018, one cm/pixel in 2019) Duke analysts created a model to detect automatically and count albatrosses.  During 2018 and 2019, the model was able to detect a total population of 268 764 nesting albatrosses on Steeple Jason and Grand Jason, with an accuracy compared to manual counts dependent upon the survey area (the model population count and accuracy for the two largest bird survey areas were 133 075 at 2.0% and 57 360 at 9.4%). These first island-wide surveys will be the basis for understanding population dynamics of a species threatened by climate change.

This model, a deep-learning algorithm called a convolutional neural network (CNN), has the capacity to be a transferrable model that can be trained and used interchangeably for researchers across the globe, which is why we are reaching out to leaders in the field to collaborate on this project. Our goals are:

1. Apply CNN to other nesting Black-browed Albatross colonies,
2. Train CNN to detect other species of albatross with similar colour patterns and nesting habits,
3. Assess CNN accuracy when transferred to colonial nesting seabirds, and
4. Assess suitability of CNN for transfer to other nesting animals.

Building upon the success of this model, WCS, Duke University and University of Tennessee – Knoxville are working together to adapt and train the CNN to detect a wide range of species in variable environments. We need tens of thousands of drone images with nesting albatrosses to input into the CNN to teach, train and validate the algorithm.  We are seeking drone imagery that fits the following criteria:

• Flight path in overlapping parallel lines with sufficient overlap to create an orthomosaic
• Sensor angle nadir, but oblique imagery would be helpful as well
• Minimum 10 000 individuals per data set
• Minimum 500 photographs per data set
• Minimum 16 MP resolution RGB camera
• Flight height recommended between 50 and 100 m, preferably below 80 m.
• Sufficiently large data set if albatross images are in a mixed colony

The software will be designed to be open source and will be available to any researcher to improve albatross research globally. If you have data you would like to contribute to these efforts and have an interest in collaborating on this project, please contact This email address is being protected from spambots. You need JavaScript enabled to view it., This email address is being protected from spambots. You need JavaScript enabled to view it. and This email address is being protected from spambots. You need JavaScript enabled to view it..”

With thanks to Wieteke Holzhuizen.

Reference:

Hayes, M.C., Gray, P.C., Harris, G., Sedgwick, W.C., Crawford, V.D., Chazal, N., Crofts, S. & Johnston, D.W. 2021.  Drones and deep learning produce accurate and efficient monitoring of large-scale seabird colonies.  Ornithological Applications Ornithological Applications  doi.org/10.1093/ornithapp/**duab022. (click here).

John Cooper, ACAP Information Officer, 03 May 2022

*A dispute exists between the Governments of Argentina and the United Kingdom of Great Britain and Northern Ireland concerning sovereignty over the Falkland Islands (Islas Malvinas), South Georgia and the South Sandwich Islands (Islas Georgias del Sur y Islas Sandwich del Sur) and the surrounding maritime areas.

 
A Grey Petrel chick starts to shed its down on Macquarie Island; photograph by ‘Jez’ Bird

Jeremy ‘Jez’ Bird (School of Biological Sciences, University of Queensland, St Lucia, Australia) and colleagues have published open access in the journal Ecography on estimating populations of burrowing seabirds ion Australia’s Macquarie Island, including that of the ACAP-listed and Near Threatened Grey Petrel Procellaria cinerea.  “Species [such as the Grey Petrel] with low abundance that occur patchily across large islands are likely to be best estimated using targeted surveys …”.

Steep!  ‘Jez’ Bird surveys burrowing petrels on Macquarie Island; photograph by Melissa Houghton

The paper’s abstract follows:

“Maximising survey efficiency can help reduce the tradeoff between spending limited conservation resources on identifying population changes and responding to those changes through management. Burrow-nesting seabirds are particularly challenging to survey because nests cannot be counted directly. We evaluated a stratified random survey design for generating unbiased population estimates simultaneously for four petrel species nesting on Macquarie Island, Australia, where the survey cue, burrow entrances, is similar for all species. We also compared the use of design-based and model-based analyses for minimising uncertainty in estimates. We recorded 2845 Antarctic prion burrows, 306 white-headed petrel burrows and two blue petrel burrows while distance-sampling along 154 km of transects. For blue petrels and grey petrels, we completed nocturnal searches along a further 71 km and searched 249 km of tracks during follow-up ground searches. We failed to generate unbiased population estimates for two rare and localised species, blue and grey petrels, from our stratified random survey. Only for the most widespread and abundant species, Antarctic prion, did the estimate have reasonable power to detect a rapid population change. Model-based analyses of the stratified random survey data did not improve upon traditional design-based analyses in terms of uncertainty in population estimates, but they did provide useful spatial representation of current populations. Models that used the targeted survey data did not reflect current population sizes and distributions of the two rare and localised species. We found that when species ecologies, distributions and abundances vary, a multi-method approach to surveys is needed. Species with low abundance that occur patchily across large islands are likely to be best estimated using targeted surveys, whereas widespread and abundant species can be accurately and precisely estimated from randomised surveys using informative model-based analyses.”

Read Jez Bird’s photo essay for the Grey Petrels of ‘Macca’ here.

With thanks to Jeremy Bird and Justine Shaw.

Reference:

Bird, J., Terauds, A., Fuller, R.A., Pascoe, P.P., Travers, T.D., McInnes, J.C., Alderman, R. & Shaw, J.D. 2022.  Generating unbiased estimates of burrowing seabird populations.  Ecography doi: 10.1111/ecog.06204.

John Cooper, ACAP Information Officer, 02 May 2022