Recovery of Sea Urchin Diadema Antillarum Populations is Correlated to Increased Coral and Reduced Macroalgal Cover

We surveyed the benthic community structure and population density of the long-spined sea urchinDiadema antillarum on the shallow fore-reefs of the Gandoca-Manzanillo Wildlife Refuge, Caribbean Costa Rica, in September and October 2004. In zones with high densities of D. antillarum (\u3e0.6 ind. m–2), the cover of non-calcareous macroalgae, known coral competitors, was low and that of live coral was high, whereas the opposite occurred in zones with low densities of D. antillarum (D. antillarum density was not related to the coverage of calcareous macroalgae, which are not viewed as coral competitors. Mean density of D. antillarum was 0.2 ind. m–2 and the total area covered by live coral was 14%. D. antillarum density and area covered by live coral were 2 and 7 times larger, respectively, than those reported 4 yr earlier for the study site. Within the same period, the proportion contributed by non-calcareous macroalgae to total algal cover declined from ~79 to 48%. Results indicate that various families of scleractinian corals in the Caribbean coast of Costa Rica have increased in abundance, that non-calcareous macroalgae have declined, and that recovering D. antillarum densities are correlated with these observations

How Effective are Posted Signs to Regulate Tourism? An Example with New Zealand Fur Seals

Increased tourism has augmented harassment to wildlife and posted signs are commonly used to manage such interactions. This study determined whether signs increased tourist compliance with regulations to remain \u3e10 m from New Zealand fur seals (Arctocephalus forsteri ) at Kaikoura Peninsula. We observed 362 tourist groups interacting with seals. The percentage of groups in which all members respected the posted distance was similar whether tourists saw the signs or not [60.6% vs. 65.9%; G(l ) = 0.98, p 0.32]. Results indicate that posted signs were ineffective in increasing compliance to regulations and suggest that alternative approaches must be considered to increase regulation compliance and better manage interactions between tourists and wildlife

Social Interactions Between Tucuxis and Bottlenose Dolphins in Gandoca-Manzanillo, Costa Rica

Studies measuring the extent of interspecific interactions between dolphin species are rare. We observed free-ranging tucuxis (Sotalia fluviatilis) and bottlenose dolphins (Tursiops truncatus) to document the frequency of occurrence of interspecific interactions relative to group size and behavioral state. We conducted opportunistic surveys in Gandoca- Manzanillo (9º36’N, 82º35’W), Costa Rica. Of the 71 groups analyzed, 46.5% were comprised only of tucuxis, 21.1% of bottlenose dolphins, and 32.4% of the two species. Social behavior was more frequent in mixed-species groups and in groups larger than four dolphins; foraging was more frequent in single-species groups and in groups smaller than five dolphins. Photographic documentation and sightings of putative hybrids suggest the occurrence of hybridization between both dolphin species. Results indicate that tucuxis and bottlenose dolphins interacted frequently and that these interactions were predominantly social in nature. Future studies will discern whether these interactions result in the development of hybrids

Year-round Algal Toxin Exposure in Free-ranging Sea Lions

Harmful algal bloom toxins cause illness and mortality in marine mammals worldwide, yet the potential for year-round exposure to these toxins has not previously been studied. We measured concentrations of domoic acid and saxitoxin in scats from Steller sea lions Eumetopias jubatus (n = 383 scats) and California sea lions Zalophus californianus (n = 125 scats) over a 2 yr period. Toxin concentrations in the scats were compared to the prey remains in the scats and to concentrations in nearshore bivalves. Saxitoxin was detected in 45% and domoic acid was detected in 17% of all scats tested, and both toxins were detected in all seasons and months of the year. A variety of benthic and pelagic fish were significantly associated with toxins in sea lion scats, including prey with low occurrence in the sea lions’ diet. Toxins detected in winter scats confirm that US West Coast marine mammals are exposed to domoic acid and saxitoxin through their prey outside of the expected algal bloom season

Long Distance Movements and Disjunct Spatial Use of Harbor Seals (Phoca Vitulina) in the Inland Waters of the Pacific Northwest

Background Worldwide, adult harbor seals (Phoca vitulina) typically limit their movements and activity toresult, the ecological impact of harbor seals is viewed as limited to relatively small spatial scales. Harbor seals in the Pacific Northwest are believed to remainsite, one of several contributing factors to the current stock designation. However, movement patterns within the region are not well understood because previous studies have used radio-telemetry, which has range limitations. Our objective was to use satellite-telemetry to determine the regional spatial scale of movements. Methodology Satellite tags were deployed on 20 adult seals (n=16 males and 4 females) from two rocky reefs and a mudflat-bay during April–May 2007. Standard filtering algorithms were used to remove outliers, resulting in an average (± SD) of 693 (±377) locations per seal over 110 (±32) days. A particle filter was implemented to interpolate locations temporally and decrease erroneous locations on land. Minimum over-water distances were calculated between filtered locations and each seal\u27s capture site to show movement of seals over time relative to their capture site, and we estimated utilization distributions from kernel density analysis to reflect spatial use. Eight males moved \u3e100 km from their capture site at least once, two of which traveled round trip to and from the Pacific coast, a total distance \u3e400 km. Disjunct spatial use patterns observed provide new insight into general harbor seal behavior. Conclusions/Significance Long-distance movements and disjunct spatial use of adult harbor seals have not been reported for the study region and are rare worldwide in such a large proportion of tagged individuals. Thus, the ecological influence of individual seals may reach farther than previously assumed

The effect of a startle-eliciting device on the foraging success of individual harbor seals (Phoca vitulina)

Pinniped predation on commercially and ecologically important prey has been a source of conflict for centuries. In the Salish Sea, harbor seals (Phoca vitulina) are suspected of impeding the recovery of culturally and ecologically critical Pacific salmon (Oncorhynchus spp.). In Fall 2020, a novel deterrent called Targeted Acoustic Startle Technology (TAST) was deployed at Whatcom Creek to deter harbor seals from preying on fall runs of hatchery chum (O. keta) and Chinook (O. tshawytscha) salmon in Bellingham, Washington, USA. Field observations were conducted in 2020 to compare the presence and foraging success of individual harbor seals across sound exposure (TAST-on) and control (TAST-off) conditions. Observations conducted the previous (2019) and following (2021) years were used to compare the effects observed in 2020 to two control years. Using photo-identification, individual seals were associated with foraging successes across all 3 years of the study. Generalized linear mixed models showed a significant 45.6% reduction in the duration (min) individuals remained at the creek with TAST on, and a significant 43.8% reduction in the overall foraging success of individuals. However, the observed effect of TAST varied across individual seals. Seals that were observed regularly within one season were more likely to return the year after, regardless of TAST treatment. Generalized linear models showed interannual variation in the number of seals present and salmon consumed. However, the effect of TAST in 2020 was greater than the observed variation across years. Our analyses suggest TAST can be an effective tool for managing pinniped predation, although alternate strategies such as deploying TAST longer-term and using multi-unit setups to increase coverage could help strengthen its effects. Future studies should further examine the individual variability found in this study.Peer reviewe

Fracturas vertebrales múltiples

Introducción: Las fracturas vertebrales múltiples son el resultado de traumatismos de alta energía. Se clasifican en contiguas cuando hay fractura de dos o más cuerpos vertebrales en forma adyacente y no contiguas cuando hay lesiones de varios niveles separadas por, al menos, una vértebra sin lesión. Objetivos: Evaluar la clínica y la cinemática de las fracturas vertebrales múltiples, establecer su distribución, evaluar la asociación con lesiones extravertebrales y detallar las complicaciones. Materiales y Métodos: Estudio multicéntrico, prospectivo y observacional de pacientes con fracturas vertebrales múltiples. Resultados: 66 pacientes (26 mujeres y 40 hombres; promedio de edad 39 años) con 196 lesiones vertebrales, 55 no tenían déficit neurológico. Cinemática: 32 accidentes automovilísticos, 27 caídas de altura, 5 traumas directos y 2 traumas deportivos. Topografía: dos C0-C3, cuatro C3-C7, ocho C7-T1, 61 T1-T10, 91 T10-L2, 28 L2-L5 y una sacro. Combinación: 21 toracolumbar-toracolumbar y 8 torácica-torácica. Treinta y dos fracturas eran contiguas; 19, no contiguas y 15 tenían un patrón mixto. Veintiséis pacientes presentaron 47 lesiones extravertebrales (20 politraumatismos), 12 traumas torácicos. Treinta y seis pacientes recibieron tratamiento conservador y 30 fueron operados. Conclusiones: La presencia de fracturas vertebrales múltiples es frecuente y son consecuencia de accidentes automovilísticos, la mayoría de los pacientes no tiene compromiso neurológico. El sector más afectado fue entre T2 y L5, la combinación más frecuente fue toracolumbar-toracolumbar, seguida de torácica-torácica. Las lesiones extravertebrales más frecuentes fueron traumatismos de cráneo y de tórax

Estimates of Chinook salmon consumption in Washington State inland waters by four marine mammal predators from 1970 to 2015

Conflicts can arise when the recovery of one protected species limits the recovery of another through competition or predation. The recovery of many marine mammal populations on the west coast of the United States has been viewed as a success; however, within Puget Sound in Washington State, the increased abundance of three protected pinniped species may be adversely affecting the recovery of threatened Chinook salmon (Oncorhynchus tshawytscha) and endangered killer whales (Orcinus orca) within the region. Between 1970 and 2015, we estimate that the annual biomass of Chinook salmon consumed by pinnipeds has increased from 68 to 625 metric tons. Converting juvenile Chinook salmon into adult equivalents, we found that by 2015, pinnipeds consumed double that of resident killer whales and six times greater than the combined commercial and recreational catches. We demonstrate the importance of interspecific interactions when evaluating species recovery. As more protected species respond positively to recovery efforts, managers should attempt to evaluate tradeoffs between these recovery efforts and the unintended ecosystem consequences of predation and competition on other protected species

Competing Tradeoff between Increasing Marine Mammal Predation and Fisheries Harvest of Chinook Salmon

Many marine mammal predators, particularly pinnipeds, have increased in abundance in recent decades, generating new challenges for balancing human uses with recovery goals via ecosystem-based management. We used a spatio-temporal bioenergetics model of the Northeast Pacific Ocean to quantify how predation by three species of pinnipeds and killer whales (Orcinus orca) on Chinook salmon (Oncorhynchus tshawytscha) has changed since the 1970s along the west coast of North America, and compare these estimates to salmon fisheries. We find that from 1975 to 2015, biomass of Chinook salmon consumed by pinnipeds and killer whales increased from 6,100 to 15,200 metric tons (from 5 to 31.5 million individual salmon). Though there is variation across the regions in our model, overall, killer whales consume the largest biomass of Chinook salmon, but harbor seals (Phoca vitulina) consume the largest number of individuals. The decrease in adult Chinook salmon harvest from 1975–2015 was 16,400 to 9,600 metric tons. Thus, Chinook salmon removals (harvest + consumption) increased in the past 40 years despite catch reductions by fisheries, due to consumption by recovering pinnipeds and endangered killer whales. Long-term management strategies for Chinook salmon will need to consider potential conflicts between rebounding predators or endangered predators and prey