Meeting to disentangle factors influencing albatross bycatch in the deep-set Hawaii Longline Fishery

By Rachael Orben PhD., Research Associate in the Seabird Oceanography Lab and GEMM Lab

Seabird bycatch is a global problem (e.g. Anderson et al 2011). Humans like eating fish and seabirds do too. Fishing vessels provide a food source for seabirds through discards, bait, and target fish. Different types of fishing gear pose different risks for seabirds. The good news is there are things that we can do to decrease these risks.

Albatrosses and petrels are particularly vulnerable to being hooked by longlines as the baited hooks are set overboard. Albatrosses and petrels are long lived (e.g., Wisdom the 65-year-old Laysan Albatross) and have a limited number of off-spring. Therefore fishery mortalities can have devastating impacts on populations if left unchecked. Currently all 22 species of albatrosses have IUCN statuses ranging from Near Threatened to Critically Endangered.

North Pacific Albatrosses

Longlines are used to catch a number of target species including tuna, swordfish, halibut, black cod, and toothfish. Just like the diversity of species this type of fishing gear is used to catch, there are a number of ways to set long-lines and ways to mitigate seabird bycatch and a method that works well in one instance may not work so well in other places. Tori Lines (a.k.a. streamer lines), side setting, night setting, faster sinking lines, and discard regulations are a few of the methods used.

Tori lines work by scaring birds away from baited longline hooks while they sink. Once the hooks sink past a few meters albatrosses are not able to reach them. Photo by Ed Melvin/Washington Sea Grant

In early November, I had the opportunity to attend a workshop in Honolulu, Hawaii hosted by the Western Pacific Regional Fishery Management Council. The workshop was held due to a dramatic increase in black-footed albatross bycatch by the Hawaii deep-set longline fishery in 2015 and 2016 (see the figure below). It was our job to figure out why, or more realistically pave the path for future analysis and data collection to answer this question.

Recently Leigh Torres and I were funded by the NOAA Bycatch Reduction Engineering Program to characterize fine-scale fishery-albatross interactions using previously collected albatross tracking data and tracks of fishing boats processed in real time by Global Fishing Watch. The workshop provided the perfect opportunity for me to learn more about the Hawaii longline fisheries.

Reasons for Albatross Bycatch

Rates of bycatch can change due to many factors, including where or when the fish are being caught, subtle choices made by fishermen, changes in seabird distributions, changes in prey of fish or seabirds, and so on. So, it can be very challenging to pin-point the exact reasons for an increase in bycatch. But, across the North Pacific, 2015 and 2016, were very strange years oceanographically. There was the warm water phenomena known as ‘the Blob’ along with a strong El Niño, and a positive Pacific Decadal Oscillation (PDO). So perhaps, bycatch levels will drop off again as we move into a La Niña, but perhaps not. It is good to know that fishery managers and scientists are paying attention.

Implications

From the perspective of the fisherman in the Hawaiian longline fleet, albatrosses are hardly ever caught; they are pulled in at a barely perceptible level of less than one bird per set and only from about December to July. Although one occasional dead bird among the menagerie of fish doesn’t seem like much, it can add up: there are ~140 boats in the deep-set longline fleet, that set 40-52 million hooks a year, plus the multiple other fisheries and fleets encountered by albatrosses across the North Pacific, and enough albatrosses could be killed to make a difference in their population numbers. And, we need to also consider the cumulative impacts since fisheries aren’t the only threat  (e.g., sea level rise, storm surges, introduced predators; see Bakker et al 2018).

Inspecting the Catch

On the morning of the last day of the workshop we took a field trip to the Honolulu Fish Market at Pier 38 in Honolulu where the Hawaiian long-line fishing vessels dock to offload and sell their catch. We checked out some of the boats, watched fish being craned off a vessel into a large cart and went inside the cooler room to see where the fish are auctioned.

In the cooler room, the catch from one vessel was laid out on brilliant blue pallets. The tails of each tuna were sliced so the deep pink color of the meat could be assessed. A core sample of each fish was laid out on an identification tag. Then the auctioneer and the buyers visited each fish, rapidly bidding on a price per pound. Their quick words were basically incomprehensible to my untrained ear.

The prize-catch of the fishery, and the fish that gets the highest price per pound, is the big eye tuna. A number of other large and beautiful pelagic species are also caught and sold including: long and narrow marlins, with their bills cut off for packing, side table size pomfrets, speckled white with red accents; and the distinctive blunt headed mahimahi, with yellow bellies. Once the fish are sold, they are moved out of the auction room, packed and loaded into the trucks that whisk them away toward markets and restaurants in Hawaii, the U.S. Mainland, and beyond.

Sustainable management of these commercially valuable fish is dependent on a better understanding of their pelagic ecosystem, including when, where, and why albatrosses interact with fishing vessels. Hopefully, our current research project will help to answer some of these questions.

Midway Atoll: Two weeks at the largest albatross colony in the world

By Rachael Orben, Postdoctoral Scholar, Seabird Oceanography Lab & Geospatial Ecology of Marine Megafauna Lab, Oregon State University

In January I was extremely lucky to accompany my former PhD advisor, Scott Shaffer to Midway Atoll National Wildlife Refuge in the Papahānaumokuākea Marine National Monument as part of my job as a postdoc working in Rob Suryan’s Seabird Oceanography LabWe were there with the dual purpose of GPS tracking Laysan and Black-footed albatrosses as part of Scott’s long-term research and to collect fine-scale data on flight behavior to develop collision risk models for wind energy development (in other areas of the species ranges such as Oregon). Here are my impressions of this amazing island.

So many albatrosses! Our approximately four hour flight from Honolulu to Midway landed at night and as we stood around on the dark tarmac greeting the human island residents I could just make out the ghostly glistening outlines of albatrosses by moonlight. But I had to wait until the following morning to really take stock of where I had suddenly landed: Midway Atoll, the largest albatross colony in the world. This was my first trip to the Northwestern Hawaiian Islands, but I have been to other albatross colonies before and Midway is most definitely different.

First of all, it was hot(ish)!

Secondly, I was amazed to see albatrosses nesting everywhere. Unlike the southern hemisphere colonies I have visited, the albatrosses aren’t restricted to their section of the island or even nesting as close to each other as possible. Instead there are nests literally everywhere there might be enough loose substrate! Birds nest in the middle of the roads, in the bike racks (bikes are an easy quick means of transportation), along the paths, next to the extremely loud generator, near piles of old equipment, and around buildings. Hawaiian albatross nests are not much to look at compared to the mud pedestal nests of the southern hemisphere mollymawks (see the photos below) and are often made of just enough sand and vegetation to keep the egg in place. There are no aerial predators of these birds, beyond the occasional vagrant peregrine, and certainly nothing that might rival the tenacity of the skuas in the southern hemisphere. Perhaps it is this naiveté that has lead to their willingness to nest anywhere.

It may also be this naiveté that has facilitated the following unfortunate turn of events. Just before I arrived, the USFWS and a crew of volunteers had just finished up the annual albatross count. During their counting sweeps they noticed injured adults incubating eggs. After setting out trail cams, suspicions were confirmed. The introduced mice on Midway have discovered that albatrosses are a source of food. House mice are known to prey on albatross chicks on Gough and Marion Islands in the South Atlantic (more information here – warning graphic photos), but to my knowledge this is the first time that they have started eating adult birds. You can read the USFWS announcement here. The plane that I flew out on brought in people, traps, and resources to deal with the situation, but stay tuned as I fear this saga is just beginning.

Finally, and on a further less than positive note, I went to Midway fully aware of the problem that plastics pose to these birds and our marine ecosystem, but there is something to be said for seeing it first hand. The chicks were very small when I was there so I didn’t see any direct impacts on them, but see below for photos of carcasses of last year’s fledglings with plastic filled stomachs. Instead, it was the shear amount of random plastic bits strewn around the island and buried layers deep into the sand that struck me. I learned that sometimes the plastic bits are glow-in-the-dark! Sometimes fishing lures have batteries in them – I am not sure what they are used to catch – do you know? And toothbrushes are very common. All of the plastic that I saw among the birds arrived in the stomach of an adult albatross. All-in-all the experience gave me renewed inspiration for continuing to reduce the amount of plastic that I use (click here for more information on albatrosses and plastic, and here and here for info on marine plastic pollution in general). I collected interesting pieces to bring home with me (see the photos below), but it is a non-random sampling of what caught my eye. I left many many plastic shards where they were.

I have written mostly about the birds, but Midway is full of human history. As I biked along the runway, or past the old officer quarters, I often found myself wondering what all these albatrosses have seen over the years and what they might witness in the future. Two weeks was really just a blink-of-an-eye for an albatross that can live over 40 years (or longer like Wisdom the albatross). I was terribly sad to leave such a beautiful place, but I came home with amazing memories, photos, and gigabytes of data that are already giving me a glimpse into the world of albatrosses at sea.

Following Tracks: A Summer of Research in Quantitative Ecology

**GUEST POST** written by Irina Tolkova from the University of Washington.

R, a programming language and software for statistical analysis, gives me an error message.

I mull it over. Revise my code. Run it again.

Hey, look! Two error messages.

I’m Irina, and I’m working on summer research in quantitative ecology with Dr. Leigh Torres in the GEMM Lab. Ironically, as much as I’m interested in the environment and the life inhabiting it, my background is actually in applied math, and a bit in computer science.

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(Also, my background is the sand dunes of Florence, OR, which are downright amazing.)

When I mention this in the context of marine research, I usually get a surprised look. But from firsthand experience, the mindsets and skills developed in those areas can actually be very useful for ecology. This is partly because both math and computer science develop a problem-solving approach that can apply to many interdisciplinary contexts, and partly because ecology itself is becoming increasingly influenced by technology.

Personally, I’m fascinated by the advancement in environmentally-oriented sensors and trackers, and admire the inventors’ cleverness in the way they extract useful information. I’ve heard about projects with unmanned ocean gliders that fly through the water, taking conductivity, temperature, depth measurements (Seaglider project by APL at the University of Washington), which can be used for oceanographic mapping. Arrays of hydrophones along the coast detect and recognize marine mammals through bioacoustics (OSU Animal Bioacoustics Lab), allowing for analysis of their population distributions and potentially movement. In the GEMM lab, I learned about light and small GPS loggers, which can be put on wildlife to learn about their movement, and even smaller lighter ones that determine the animal’s general position using the time of sunset and sunrise. Finally, scientists even made artificial nest mounds which hid a scale for recording the weight of breeding birds — looking at the data, I could see a distinctive sawtooth pattern, since the birds lost weight as they incubated the egg, and gained weight after coming home from a foraging trip…

On the whole, I’m really hopeful for the ecological opportunities opened up by technology. But the information coming in from sensors can be both a blessing and a curse, because — unlike manually collected data — the sample sizes tend to be massive. For statistical analysis, this is great! For actually working with the data… more difficult. For my project, this trade-off shows as R and Excel crash over the hundreds of thousands of points in my dataset… what dataset, you might ask? Albatross GPS tracking data.

In 2011, 2012, and 2013, a group of scientists (including Dr. Leigh!) tagged grey-headed albatrosses at Campbell Island, New Zealand, with small GPS loggers. This was done in the summer months, when the birds were breeding, so the GPS tracks represent the birds’ flights as they incubated and raised their chicks. A cool fact about albatrosses: they only raise one chick at a time! As a result, the survival of the population is very dependent on chick survival, which means that the health of the albatrosses during the breeding season, and in part their ability to find food, is critical for the population’s sustainability. So, my research question is: what environmental variables determine where these albatrosses choose to forage?

The project naturally breaks up into two main parts.

  • How can we quantify this “foraging effort” over a trajectory?
  • What is the statistical relationship between this “foraging effort metric” and environmental variables?

Luckily, R is pretty good for both data manipulation and statistical analysis, and that’s what I’m working on now. I’ve just about finished part (1), and will be moving on to part (2) in the coming week. For a start, here are some color-coded plots showing two different ways of measuring the “foraging value” over one GPS track:

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Most of my time goes into writing code, and, of course, debugging. This might sound a bit dull, but the anticipation of new results, graphs, and questions is definitely worth it. Occasionally, that anticipation is met with a result or plot that I wasn’t quite expecting. For example, I was recently attempting to draw the predicted spatial distribution of an albatross population. I fixed some bugs. The code ran. A plot window opened up. And showed this:

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I stared at my laptop for a moment, closed it, and got some hot tea from the lab’s electronic kettle, all the while wondering how R came up with this abstract art.

All in all, while I spend most of my time programming, my motivation comes from the wildlife I hope to work for. And as any other ecologist, I love being out there on the Oregon coast, with the sun, the rain, sand, waves, valleys and mountains, cliff swallows and grey whales, and the rest of our fantastic wild outdoors.

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