Cristián G. Suazo

High occurrence of jellyfish predation by black-browed and Campbell albatross identified by DNA metabarcoding

Gelatinous zooplankton are a large component of the animal biomass in all marine environments, but are considered to be uncommon in the diet of most marine top predators. However, the diets of key predator groups like seabirds have conventionally been assessed from stomach content analyses, which cannot detect most gelatinous prey. As marine top predators are used to identify changes in the overall species composition of marine ecosystems, such biases in dietary assessment may impact our detection of important ecosystem regime shifts. We investigated albatross diet using DNA metabarcoding of scats to assess the prevalence of gelatinous zooplankton consumption by two albatross species, one of which is used as an indicator species for ecosystem monitoring. Black‐browed and Campbell albatross scats were collected from eight breeding colonies covering the circumpolar range of these birds over two consecutive breeding seasons. Fish was the main dietary item at most sites; however, cnidarian DNA, primarily from scyphozoan jellyfish, was present in 42% of samples overall and up to 80% of samples at some sites. Jellyfish was detected during all breeding stages and consumed by adults and chicks. Trawl fishery catches of jellyfish near the Falkland Islands indicate a similar frequency of jellyfish occurrence in albatross diets in years of high and low jellyfish availability, suggesting jellyfish consumption may be selective rather than opportunistic. Warmer oceans and overfishing of finfish are predicted to favour jellyfish population increases, and we demonstrate here that dietary DNA metabarcoding enables measurements of the contribution of gelatinous zooplankton to the diet of marine predators.

Evolutionary factors affecting the cross‐species utility of newly developed microsatellite markers in seabirds

Microsatellite loci are ideal for testing hypotheses relating to genetic segregation at fine spatio‐temporal scales. They are also conserved among closely related species, making them potentially useful for clarifying interspecific relationships between recently diverged taxa. However, mutations at primer binding sites may lead to increased nonamplification, or disruptions that may result in decreased polymorphism in nontarget species. Furthermore, high mutation rates and constraints on allele size may also with evolutionary time, promote an increase in convergently evolved allele size classes, biasing measures of interspecific genetic differentiation. Here, we used next‐generation sequencing to develop microsatellite markers from a shotgun genome sequence of the sub‐Antarctic seabird, the thin‐billed prion (Pachyptila belcheri), that we tested for cross‐species amplification in other Pachyptila and related sub‐Antarctic species. We found that heterozygosity decreased and the proportion of nonamplifying loci increased with phylogenetic distance from the target species. Surprisingly, we found that species trees estimated from interspecific FST provided better approximations of mtDNA relationships among the studied species than those estimated using DC, even though FST was more affected by null alleles. We observed a significantly nonlinear second order polynomial relationship between microsatellite and mtDNA distances. We propose that the loss of linearity with increasing mtDNA distance stems from an increasing proportion of homoplastic allele size classes that are identical in state, but not identical by descent. Therefore, despite high cross‐species amplification success and high polymorphism among the closely related Pachyptila species, we caution against the use of microsatellites in phylogenetic inference among distantly related taxa.

Fishermen's perceptions of interactions between seabirds and artisanal fisheries in the Chonos archipelago, Chilean Patagonia

Interactions between seabirds and commercial fishing activities have been well documented but little information is available regarding the impacts of more traditional fishing practices on seabird populations. We interviewed fishermen, administered questionnaires, and made field-based observations to determine the extent to which artisanal fisheries interact with and affect seabirds in the fjords and channels of the Chonos archipelago in southern Chile. Our surveys indicated a positive perception of seabirds as useful indicators of marine productivity and in their role scavenging fish waste and discards associated with fishing operations. However, the surveys also revealed that fishermen routinely establish seasonal camps for collecting seabird eggs and adults for food or bait and introduce feral predators to seabird breeding colonies on islands. Understanding the traditional practices of fisher- men is critical for the future of community-based conservation of the regions marine resources and biodi-

Emerging platforms to monitor the occurrence and threats to critically endangered seabirds: The waved albatross in Chile and the Southeast Pacific

espanolLas especies de aves marinas longevas, tales como albatros y petreles ampliamente distribuidos en el mar y con poblaciones reducidas, tienen a la captura incidental en pesquerias como una de las principales amenazas para su conservacion. Entre estas, el albatros de Galapagos Phoebastria irrorata es escasamente detectado en las Zonas Economicas Exclusivas (ZEE) de paises mas alla de su distribucion tradicional a lo largo del Pacifico Sudeste. En este articulo se recopilan registros distribucionales del albatros de Galapagos in situ y obtenidos desde observaciones no sistematicas en el mar, tales como actividades de turismo (i.e., observacion pelagica de aves) desde la decada de 1980s en adelante. A su vez, se incorporan registros desde monitoreos sistematicos en pesquerias de palangre y arrastre, operando entre el norte y centro-sur de Chile (Pacifico Sudeste). La ocurrencia de avistamientos fue analizada segun caracteristicas ambientales relacionadas a estos, como presencia/ausencia de periodo reproductivo e indicadores de eventos El Nino, tal como valores negativos en el Indice de Oscilacion Sur (IOS), entre otros. Se describio un total de 13 avistamientos del albatros de Galapagos y con 76,9% de estos fuera de su periodo reproductivo (diciembre a abril). Los registros evidencian una distribucion meridional del albatros de Galapagos hasta el centro-sur de Chile (38°S), alcanzando 4.391 km al sur de Islas Galapagos, asi como hasta 920 km al oeste (79°O) desde la costa Sudamericana. El albatros de Galapagos fue registrado en asociacion con pesquerias industriales de palangre pelagico y arrastre demersal. No hubo registros de captura incidental, aunque la observacion de individuos asociados a barcos de estas pesquerias para alimentarse de descartes y eviscerados sugiere un potencial riesgo de mortalidad para esta especie. El 53,8% de los avistamientos fueron durante lecturas positivas del Indice de Oscilacion Sur (IOS), representando condiciones mas frias que las neutrales de El Nino Oscilacion Sur (ENOS). EnglishLong-lived seabird species such as albatrosses and petrels, which are widely distributed at sea and have small populations are threatened globally by bycatch in fisheries. Among these, the waved albatross Phoebastria irrorata is scarcely detected in the Exclusive Economic Zones (EEZs) of countries beyond its traditional distribution throughout the Southeast Pacific. In this article, in situ distributional records on the waved albatross obtained from non-systematic (pelagic birdwatching) and systematic (fishery monitoring) records were compiled. Occurrence of sightings was carried out in relation to recording traits as presence/absence of breeding period and El Nino proxies such as the Southern Oscillation Index (SOI), among others. A total of 13 sightings of waved albatrosses was described which 76.9% of sightings were related to non-breeding period (December to April). Records indicated waved albatrosses reached 4,391 km south of the Galapagos Islands (38°S) and 920 km west of the South American coast (79°W). The waved albatross was associated with industrial pelagic longline and demersal trawl fisheries, and although there were no records of bycatch, the observation of individuals feeding on discards and offal suggests a potential risk of mortality for this species. 53.8% of sightings were during positive readings of the Southern Oscillation Index (SOI), representing colder conditions than neutral El Nino Southern Oscillation (ENSO).