Seabirds

Range and threats

• Albatrosses roam vast areas of the Pacific, often concentrating in productive zones where fisheries operate. This overlap has historically led to significant bycatch: roughly two-thirds of global seabird longline mortalities are estimated to occur in the North Pacific (above ~20°N), and about one-quarter in the far South Pacific (south of 30°S). These regions correspond to where Laysan, Black-footed, and other albatrosses forage in the north, and where species like Wandering and Shy Albatross forage in the south. Without mitigation, thousands of albatrosses were being killed annually in these fisheries.
• Even small increases in adult mortality can crash albatross populations. For example, ACAP identified the Antipodean Albatross (endemic to New Zealand) as facing an extreme decline – about 5% fewer adults each year – primarily due to females getting caught on longline hooks. Models predict that if current bycatch levels continue, this albatross could decline by over 80% in one generation. Similar trends have been observed in other albatross species, underscoring how critical it is to prevent every possible fatality of these slow-breeding birds.
• International cooperation is key. Albatross migrations span multiple jurisdictions – for instance, a single albatross may feed in the high seas, in WCPFC waters, and in the Eastern Pacific (IATTC area) during one year. To protect them throughout their range, WCPFC collaborates with ACAP and other RFMOs via formal agreements (an ACAP–WCPFC Memorandum of Understanding was signed in 2007). This ensures consistent bycatch mitigation measures across ocean basins. Data on albatross movements and bycatch is shared internationally so that conservation actions (such as mitigation requirements or area closures) can be synchronized for maximum benefit.

Mitigation and best practices

• Multiple deterrents at once: Experience has shown that using a combination of mitigation measures is far more effective than any single measure alone. For example, setting lines at night *and* using properly designed tori lines *and* weighted hooks provides three layers of protection – greatly reducing the chance an albatross can grab a bait. ACAP’s best-practice advice recommends this integrated approach, and WCPFC rules require at least two measures in core albatross habitat areas. Where fleets (such as the Hawaii longline fishery) have adopted these measures, albatross bycatch has dropped dramatically, demonstrating that “doing it all” pays off in near-zero seabird catches.
• New technologies: In recent years, novel mitigation technologies have emerged. One example is hook-shielding devices – essentially sleeves or capsules that cover the hook and bait until it sinks to a preset depth (e.g., 10–20 m). These devices prevent any bird (albatross or otherwise) from accessing the hook near the surface. WCPFC now recognizes hook-shielding devices as an alternative stand-alone measure to meet mitigation requirements. Trials have shown they virtually eliminate seabird hookings at the surface. Other innovations include underwater bait-setting machines (to deploy hooks below the surface), and smart weighted lines that sink extremely fast. WCPFC keeps its measures under review to incorporate proven new methods; for instance, if a technology like an underwater setter becomes practical for broad use, it could be added as an approved mitigation option in the future.
• Crew training and compliance: Ensuring that mitigation measures are not only available but correctly used is crucial. WCPFC member countries conduct training workshops and outreach for vessel operators on how to implement seabird bycatch measures. This includes showing crews how to rig and deploy tori lines at the proper height and distance, how to handle weighted lines safely, and why it’s important to avoid excess lighting or offal discharge during night sets. Observers and electronic monitoring systems actively check that vessels are using the required measures and using them properly. High compliance is rewarded by sharply lower bycatch rates – for example, on vessels that strictly follow all guidelines, it’s not uncommon to go an entire fishing season with zero albatrosses caught. Conversely, if a vessel fails to deploy mitigation (or does it incorrectly), observers often document higher seabird attendance and occasional captures, reinforcing the need for constant diligence.

Monitoring and research

• Improved bycatch data: The WCPFC Scientific Committee has highlighted the need for better data to evaluate seabird bycatch trends. In response, WCPFC adopted new reporting guidelines so that all members report seabird interactions in a standardized way (including details like species ID and which mitigation was in use). Observer coverage is being incrementally increased, and electronic monitoring (cameras on boats) is being introduced to supplement human observers, especially in fleets with low coverage. These steps help scientists get a more accurate estimate of total albatross mortality and assess which fisheries or areas might need additional attention. They also enable analysis of mitigation effectiveness – for instance, comparing bycatch rates before vs. after the 2018-03 measure to ensure it’s achieving the expected reductions.
• Population monitoring: Outside of fisheries, researchers continually monitor albatross breeding colonies to track population health. On important breeding islands (such as in Hawaii, Japan, New Zealand), annual or periodic counts of nesting pairs, as well as banding and re-sighting programs, provide insight into survival and breeding success. ACAP compiles these data to produce species assessments and trend analyses. If bycatch mitigation is working, one would expect to see adult survival rates improve and population declines slow or reverse over time. Some albatross populations (e.g., Laysan Albatross on Midway Atoll) have indeed shown stable or increasing trends in the last two decades, coinciding with intensive bycatch prevention efforts. Continued monitoring is essential to detect any negative changes early. It also helps identify emerging threats – for example, if a population is not recovering despite low reported bycatch, factors like climate change or pollution might be investigated.
• Collaboration and future research: Albatross conservation in the WCPO is part of a larger global effort. WCPFC works closely with other RFMOs and conservation bodies. ACAP’s Seabird Bycatch Working Group provides updated technical advice every few years, which WCPFC considers for refining its measures. Collaborative research, such as tagging studies, helps to map albatross migrations with ever greater precision – critical for predicting overlap with fisheries. Looking ahead, there is interest in habitat modeling to predict how oceanographic changes (e.g., shifting currents or warming seas) might alter albatross foraging ranges, which could in turn require adaptive management by WCPFC. By staying proactive and science-based, the goal is to keep strengthening bycatch mitigation so that albatross populations not only stop declining but begin to recover throughout the Pacific.

Ecology and interactions

• Boobies (family Sulidae) are abundant in tropical Pacific regions, breeding on remote islands and foraging primarily in nearby waters. Species such as the Red-footed Booby, Brown Booby, and Masked Booby are commonly seen around coral atolls and archipelagos, where they feed on schooling fish driven to the surface by predators. These birds can travel tens or even hundreds of kilometers from their nesting colonies to find food, but they usually remain within range of land to roost at night. Gannets (closely related to boobies) have a similar ecology in subtropical areas – for example, the Australasian Gannet forages on continental shelf waters around New Zealand and southern Australia. Because of this coastal/nearshore foraging pattern, boobies and gannets infrequently encounter tuna longline vessels, which often operate far offshore. This limited overlap is a primary reason why their bycatch is very low.
• In terms of behavior, boobies and gannets hunt by sight during daylight. They locate prey from the air and dive steeply into the ocean at high speed to catch fish below the surface. Unlike albatrosses or petrels, they do not typically scavenge behind fishing vessels for offal (though they may pick up discarded bycatch on occasion). They also have the ability to fully submerge and swim briefly underwater when pursuing prey. These traits mean that a baited longline hook, which is attached to a moving vessel and sinks beneath the surface, is not an easy target for a booby. Indeed, fisheries data indicate that boobies and gannets rarely get hooked – they either ignore the moving baits or fail to get the bait off the hook before it sinks. In one study, Pacific longline skippers reported only occasional interactions with boobies, mostly involving curious Brown Boobies grabbing trolled bait scraps without getting snagged. Such incidents were minor and almost never resulted in injury to the bird.
• Recorded bycatch instances are extremely scarce. Over 2007–2016, WCPFC observers documented nearly 1,000 seabirds caught in longline fisheries, the vast majority being albatrosses and petrels, and zero boobies or gannets among those records. In the purse seine fishery (which operates in equatorial waters where boobies reside), only 15 seabird captures were recorded in the same ten-year period. Those few incidents likely involved boobies diving into nets or roosting on fishing gear; all available evidence suggests such events are exceptionally rare. This aligns with observations that boobies/gannets are adept fliers and can evade danger – they are often seen flying around purse seine nets to snatch small fish, but quickly retreat once the net starts to close. Overall, their natural wariness and the brief exposure of fishing gear at the surface translate into a very low risk of entanglement or hooking for these birds.

Mitigation and oversight

• Leverage existing measures: Although no special rules target boobies and gannets, the general seabird-safe fishing practices promoted by WCPFC also benefit these birds. For instance, skippers are encouraged to avoid chumming or dumping fish waste while setting lines, especially in areas where any seabirds are present. This is a simple step that can prevent attracting boobies to the vessel. Similarly, if a vessel happens to be fishing near an island colony (where boobies might be feeding), using a tori line or weighted hooks – even if not mandated – provides an extra safeguard. Since these mitigation tools are already on hand for use in higher latitudes, many fishermen apply them opportunistically in the tropics when they notice bird activity. This voluntary uptake helps keep booby/gannet bycatch near zero.
• Safe release and reporting: WCPFC’s guidelines for handling bycaught seabirds apply equally to all species. In the uncommon event that a booby or gannet is hooked or entangled, crew are instructed to gently bring the bird onboard (if it’s safe to do so) and remove the hook or line using a de-hooker or line-cutter, then release the bird in a recovered condition. Because boobies have relatively small bills (compared to albatrosses), they are easier to handle without injury; many fishermen are familiar with freeing them from recreational hooks near shore. These events are so rare in WCPO fisheries that they’re mainly anecdotal, but the principle is clear: every effort should be made to release the bird unharmed. Additionally, any such interaction must be recorded in the logbook and reported. By maintaining this documentation, WCPFC can detect if booby/gannet interactions start rising for any reason. To date, the consistently low reports confirm that current practices are effective in avoiding harm to these species.
• Future considerations: While boobies and gannets are not currently impacted by WCPO tuna fisheries, WCPFC remains vigilant. If climate change or ecosystem shifts lead these birds to range more widely offshore (potentially increasing overlap with fisheries), the Commission can adapt its measures. For example, if a particular area or season saw increased booby activity around fishing vessels, WCPFC could consider extending mandatory mitigation into that area/season. The Commission’s precautionary approach and cooperation with experts (like BirdLife International and ACAP) ensure that even species not presently at risk stay on the radar. In essence, the absence of a problem now doesn’t preclude action later if needed. Fortunately, boobies and gannets in the Pacific are currently faring well, and continued monitoring – both at colonies and at sea – will help keep it that way.

Range and interactions

• Petrels and shearwaters occupy diverse niches across the Pacific. Some, like the Wedge-tailed Shearwater or Tropical Shearwater, breed on tropical islands and forage near those regions year-round. Others are long-distance migrants: the Black Petrel, for example, breeds in New Zealand but spends its non-breeding season in the eastern tropical Pacific (off South America), crossing the breadth of the WCPO in the process. Large petrels of the genus Procellaria (Black, Westland, White-chinned, Grey Petrel) mostly breed in the New Zealand region and forage widely in the South Pacific, often in sub-tropical and temperate waters where tuna and swordfish longline effort is significant. Wherever these birds overlap with baited longlines, there is potential for bycatch. Petrels and shearwaters are bold and often feed in groups; a single longline set can attract dozens of them. This group also includes strong divers – for instance, Black Petrels have been recorded diving to at least 38 meters depth. Their diving ability means that even night setting or quick-sinking baits can sometimes be intercepted. Indeed, in the absence of comprehensive mitigation, petrels/shearwaters (over ~500 g) have proven to be the most frequently caught seabirds in many fisheries.
• Certain “hotspot” areas have been identified for petrel bycatch. By analyzing observer data, scientists found high petrel catch rates in the vicinity of New Zealand and adjacent high seas – correlating with the foraging range of species like Westland and White-chinned Petrels. Another area of concern is the Humboldt Current region off South America (outside WCPFC’s area) where many Black Petrels and Pink-footed Shearwaters winter; bycatch there can impact the populations that breed in the WCPO. Within the WCPFC area, the highest mortalities occur south of 25°S (hence the emphasis on mitigation in those latitudes). Equatorial waters generally have fewer petrels (most tropical species like gadfly petrels are smaller and not as attracted to longlines), but there are exceptions – for example, Flesh-footed Shearwaters in the North Pacific subtropics have been caught in some fisheries. Overall, mapping petrel/shearwater distributions against fishing effort is an ongoing effort. ACAP and WCPFC members use tracking data and observer records to continually refine our understanding of where interactions are most likely, so that management can be targeted appropriately.
• A special note on Procellaria petrels: these large petrels are notorious in bycatch statistics. They are aggressive, surface-seizing birds that will dive and fight over baits, often defeating basic mitigation like single tori lines. They have even been observed pulling hooked fish or bait to the surface, which can cause a chain reaction of other birds getting hooked (so-called “secondary attacks”). All Procellaria species in the region (White-chinned, Black, Westland, Grey Petrel) are either Vulnerable or Endangered and have been prioritized for action by ACAP. Their behavior makes them challenging to protect – even well-implemented mitigation can occasionally fail if these petrels are abundant. This is why ACAP continually researches improved measures specifically with Procellaria in mind, and WCPFC members pay close attention to any rises in their bycatch rates.

Mitigation strategies

• Depth and sink rate matter: Since many petrels and shearwaters can dive to substantial depths, a key mitigation goal is to get hooks out of reach as fast as possible. ACAP recommends using weighted branch lines that ensure hooks sink beyond 10 m depth quickly, especially important given Black Petrels commonly dive >10 m and occasionally to ~40 m. In practice, this means adding sufficient weight (e.g., 60–120 g) near the hook. However, weighting alone is not enough – birds can still grab the bait in the few seconds before it sinks deeply. Thus, weights must be paired with bird-scaring lines (tori lines) to physically block birds from reaching the bait during those critical seconds, and/or night setting to make the bait harder to locate. The combination of these measures has proven effective: for example, experimental studies in New Zealand waters showed that when lines were both well-weighted and protected by tori lines, petrel catches dropped to very low levels. In short, an integrated approach is essential – a multi-pronged defense to keep determined diving birds at bay until the gear is safely deep.
• Hook-shielding devices: One of the promising newer tools for petrel bycatch prevention is the hook-shielding pod. By encapsulating the hook, these devices render the bait inaccessible during the entire duration of its drop through the danger zone. Petrels chasing the sinking bait simply cannot get the hook until it’s far below. WCPFC’s measure allows hook-shielding devices as a standalone alternative to using tori lines + weights. Trials, particularly with White-chinned Petrels in New Zealand’s fisheries, have shown near-zero seabird catches when every hook was shielded. The trade-off is the added cost and handling of the devices, but some fleets are beginning to adopt them for the added protection they offer. Alongside hook-shielders, other innovations like double-weighted lines (two weights per branch line to speed sinking) or dyeing baits blue (to make them less visible to birds) have been tested. While not all experiments show significant benefits, the suite of options gives fishermen flexibility to find what works best for their operation. WCPFC keeps an eye on these developments – any technique that consistently reduces petrel/shearwater mortality can be incorporated into future guidelines.
• Offal management and bait safety: One often overlooked factor in petrel bycatch is the attraction of fishing vessels due to offal (fish waste) discards. Petrels have an excellent sense of smell and are quickly drawn to vessels that are discharging fish heads, guts, or unused bait. If a flock of petrels is busy scavenging behind a boat, they are much more likely to notice and attack baited hooks during setting. Therefore, best practice is for vessels to retain offal during line setting and only release it once the setting is finished (or when no birds are around). Some vessels have equipment to macerate offal into tiny pieces, which is thought to reduce the incentive for birds to chase it. Ensuring that bait is properly thawed (so it sinks faster) and not throwing any bait overboard outside of the hooks on the line are additional precautions. These work in tandem with mandated measures: for example, even with a tori line out, if a vessel dumps a stream of fish waste, petrels might dive under the tori line to reach it and then also grab hooks. By minimizing attractants (like offal and garbage) and keeping a “clean” wake, fishermen can significantly reduce the number of birds that approach close to danger.
• Species identification and data: Because many petrels and shearwaters look alike, especially in the field, WCPFC has emphasized improving species identification in bycatch records. Observer training now includes identification of key petrels (for instance, differentiating a White-chinned Petrel from a Flesh-footed Shearwater, or a Black Petrel from a Westland Petrel). WCPFC, with ACAP’s help, developed seabird identification guides with photos and descriptions to aid this effort. Accurate data is crucial: if we know exactly which species are being caught and where, managers can tailor mitigation more precisely. For example, if observers report that nearly all petrel bycatch south of 40°S are White-chinned Petrels, that underscores the need to work with CCAMLR (the Antarctic fisheries body) as those birds move between WCPFC and CCAMLR areas. Likewise, if Black Petrels turn up in significant numbers in a certain fishery north of New Zealand, WCPFC can target that fishery for outreach and perhaps additional measures during the months Black Petrels are present. In summary, better identification and reporting lead to better conservation actions.

Monitoring and research

• Colony-based monitoring: Many petrels and shearwaters are endemic breeders on a limited number of islands, making colony monitoring vital for assessing population status. In New Zealand, for instance, both Black Petrel and Westland Petrel colonies are monitored annually or semi-annually – researchers count burrows, band adults and chicks, and check survival rates. Recent surveys suggest Black Petrel numbers have at least stabilized, likely owing to intensive predator control at the breeding sites and improved bycatch mitigation at sea. Westland Petrel may even be increasing slightly in number as of the latest census, which is an encouraging sign. These trends will be watched closely. Additionally, some of the most endangered tropical petrels (e.g., Fiji Petrel, which is Critically Endangered) are subjects of ongoing search and monitoring efforts; while such species are not known to be impacted by fisheries (they are so rare that bycatch has never been recorded), any information on their population trajectory is valuable. WCPFC members support on-the-ground conservation (through programs like the Pacific Islands Trust) recognizing that protecting breeding habitats complements at-sea measures.
• Tracking and telemetric studies: Advances in miniature tracking devices (satellite tags, GPS loggers, geolocators) have revolutionized our knowledge of petrel and shearwater movements. Researchers have tagged individuals of species like the Black Petrel, White-chinned Petrel, and Flesh-footed Shearwater to map their migratory routes and feeding areas. These studies have directly informed WCPFC discussions – for example, knowing that Black Petrels spend months off the coast of Peru/Ecuador has spurred increased data-sharing with IATTC (the Eastern Pacific RFMO) to ensure those birds aren’t facing unmitigated bycatch there. Likewise, tracking Westland Petrels revealed frequent use of seas east of New Zealand, leading that country to extend its domestic mitigation measures year-round in those waters (beyond WCPFC’s seasonal requirements). As tracking continues, we gain insight into how petrel distributions shift with ocean conditions; this will help WCPFC anticipate future bycatch hotspots. If, say, ocean warming pushes certain prey species further south, petrels might alter their range – managers could then proactively expand mitigation to new areas if needed.
• Collaboration and cross-treaty efforts: Petrels and shearwaters are a shared responsibility among many nations. WCPFC engages with ACAP’s working groups for technical guidance and with other RFMOs to ensure our measures are up to global standards. For instance, ACAP regularly updates its best-practice advice (e.g., recommending minimum sink rates for hooks, minimum tori line specifications) and WCPFC considers these updates for incorporation at Commission meetings. There is also collaboration through workshops and joint research projects. A recent example is a cooperative study on diving behavior of petrels in the WCPO, involving New Zealand and U.S. scientists, which has provided direct input on how deep hooks need to be protected. WCPFC also looks to domestic initiatives like Australia’s and New Zealand’s seabird bycatch plans for inspiration on improving compliance and innovation. Through these multi-organization efforts, the gap between science and management is narrowed, ultimately benefitting the conservation of petrels and shearwaters across the Pacific.

Occurrence and risk

• Most gulls (Larus spp.) are coastal feeders and are rarely seen far from land in the WCPO. For example, the Black-tailed Gull and Slaty-backed Gull are common in East Asian coastal waters but do not venture into the central Pacific. Terns (such as Sooty Terns, Noddy terns, and various tropical species) do forage at sea but usually in association with land (breeding colonies on islands) or with surface-schooling tuna. They feed on small fish driven up by tuna schools, a very different scenario than chasing bait on a longline hook. These feeding frenzies often occur around drifting objects or FADs, where purse seiners operate, but the birds are adept at staying above the net and are seldom caught. Skuas and jaegers (Pomarine Skua, Long-tailed Jaeger, etc.) migrate through the Pacific and are occasionally seen harassing terns or boobies for food. They are “piratical” feeders but not known to take longline baits. In fact, skuas crossing the tropics are usually on migration and not actively feeding. Observer data corroborate that these birds have an extremely low overlap with fishing gear: in Pacific Island longline fisheries, no skuas and only an exceedingly few terns have ever been noted caught. This indicates that their at-sea distribution and behavior keep them largely out of trouble with regard to tuna fishing.
• Another factor is the geographic separation of fishing effort and these birds’ core habitats. Tuna longlining is most intense in the open ocean between roughly 10°N and 20°S and again in bands around 30°–40° in both hemispheres. Gulls are virtually absent from the equatorial belt (there are no “pelagic gull” species regularly there), and in the southern 30°–40°S band, the seabird fauna is dominated by albatrosses and petrels, not gulls. Sooty Terns and other tropical terns do live in equatorial waters, but they feed on live prey at the surface and are not attracted to fishing vessels in the way that albatrosses/petrels are. Skuas from the south (e.g., South Polar Skuas) migrate into the North Pacific and vice versa, but during migration they spend a lot of time resting on the water or flying – their feeding is minimal, and they don’t particularly seek out fishing boats. The bottom line is that by sheer luck of distribution, the main tuna fisheries and the main concentrations of gulls/terns/skuas don’t coincide in a hazardous way. This fortunate situation is reflected in the lack of bycatch records over decades of monitoring.
• It’s worth noting that while tuna fisheries aren’t impacting these birds, other human activities sometimes do – for example, egg harvesting and introduced predators can threaten tern colonies, and plastic pollution is a growing issue (many terns and gulls ingest plastic). However, those impacts are outside WCPFC’s mandate. From the WCPFC perspective, gulls, terns, and skuas currently require no special intervention simply because they don’t significantly interact with the fisheries under our management. They remain an important part of the Pacific ecosystem, of course, and WCPFC’s ecosystem approach means we keep a watch on all such components. If any unusual incidents (say, a gull entangled in a longline, or a tern flock diving on baits) were reported, they would be examined carefully. To date, no such pattern has emerged, confirming that these birds are at minimal risk from WCPO tuna fishing operations.

Mitigation and policy

• General mitigation measures: The seabird bycatch measures WCPFC has in place (like tori lines, night setting, etc.) were designed with albatrosses and petrels in mind, but they also incidentally protect any gulls, terns, or skuas that might be around. For example, if a vessel uses a tori line in the North Pacific (as required), that line will also deter any Black-tailed Gulls or Arctic Terns in the area from approaching the hooks. In the unlikely scenario that flocks of terns start following vessels (perhaps around drifting FADs), the crew could apply the same strategies – such as deploying scare lines or waiting for night – to avoid catching them. Because these birds are agile and mostly day-active, simply setting gear at night (standard practice in swordfish longlining) effectively eliminates their interaction. In essence, the existing toolset is perfectly adequate for preventing bycatch of gulls, terns, and skuas, to the point that no additional specialized tools have been deemed necessary.
• Legal and reporting framework: All WCPFC members are obligated by the Convention (Article 5) to minimize catch of non-target species and protect biodiversity. This overarching duty extends to even those species that aren’t covered by specific CMM provisions. Therefore, if gulls, terns, or skuas were to start interacting with a fishery, members would be expected to take action under that general obligation. In practical terms, any interaction must be recorded by observers and reported annually. The Commission’s Annual Report Part 1 includes a section for reporting seabird catches by species (or species group) – so far, reports show zero or near-zero entries for gulls/terns/skuas, indicating how seldom they feature. Nonetheless, this reporting requirement ensures transparency; were a problem to arise, it would be visible in the data. The requirement to release any captured seabird alive, mentioned in WCPFC guidelines, applies equally to these birds, though in reality fishermen rarely if ever find themselves needing to free a gull or tern from a hook in WCPO fisheries.
• Continued monitoring: Even though gulls, terns, and skuas are “off the radar” in terms of bycatch, monitoring efforts continue to include them by default. WCPFC’s regional observer program collects data on all seabird interactions, so observers are briefed that if they ever see a gull or tern caught, it should be noted and photographed for ID. This hasn’t really occurred, which is reassuring. Outside the fisheries arena, many WCPFC members engage in conservation of these birds through other agreements or national programs – for instance, countries protect important breeding sites for terns and conduct surveys of migrating skuas. By maintaining links between these broader conservation efforts and fisheries management, WCPFC ensures that any emerging issue can be caught early. Should climate or ecosystem changes alter the behavior of these species (for example, some evidence suggests certain tropical tern species might venture farther offshore as ocean climates shift), WCPFC can respond by adjusting mitigation advice. In summary, while gulls, terns, and skuas currently require little direct intervention from WCPFC, the Commission remains committed to the principle of vigilance, ensuring that all seabird species, common or rare, are safeguarded as part of the WCPO’s marine biodiversity.