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Humpback whales wintering in the entire West Indies chain are widely treated as comprising a single breeding population. However, most areas outside of Silver Bank and Samana Bay, Dominican Republic, are poorly and sporadically studied. Data is presented on the timing and movement patterns of 262 whales from the southeastern Caribbean, extending from Antigua in the north to Trinidad and Tobago in the south. Whales from the area were re-sighted in all of the major North Atlantic feeding grounds. However, of the 43 individuals re-sighted in feeding areas, animals from eastern feeding grounds were significantly over-represented, while those from western feeding areas were under-represented. This is in direct contrast to the pattern previously demonstrated in the Dominican Republic. Supporting this finding, the proportion of whales showing visible scarring on the flukes from non-lethal attack by killer whales was similar to that previously shown for Norway; yet lower than that presented from western feeding areas. The seasonal pattern of distribution in the southeastern Caribbean shows a peak of occurrence about six weeks later than in the Dominican Republic, and there is little overlap in the periods of greatest use. Sightings are uncommon before February. The peak in abundance occurs during March and April, declining during May, with some sightings extending into June. This is consistent with the pattern of sightings from historical whaling records in the southeastern Caribbean. These results suggest that the humpbacks mating and calving in this region are not a representative subset of those that winter in the Dominican Republic. Further studies will be needed to examine the spatial nature of the pattern shown here and define the nature and limits of this group, but these results suggest that some part of this breeding area represents a previously un-described distinct population segment within the North Atlantic. Given this, the widely held idea that there is a single West Indies humpback whale distinct population segment is in need of reconsideration.

Estudos com epocas de semeadura sao importantes ferramentas no processo de adaptacao e estabilidade de hibridos de canola. O objetivo em realizar este trabalho foi avaliar os subperiodos: emergencia ao inicio do florescimento (EIF), duracao do florescimento (DFL), duracao da maturacao (DMA) e ciclo, bem como o desempenho agronomico de hibridos de canola em diferentes epocas de semeadura. O experimento foi conduzido no Parana entre 07/04/ e 25/10/2018, num delineamento de blocos casualizados com quatro repeticoes em esquema de parcelas subdividas. As parcelas foram compostas por seis epocas de semeadura (07 e 22/04, 07 e 22 /05 e 06 e 21/06) e as subparcelas por cinco hibridos de canola (Hyola 50, Hyola 61, Hyola 433, Hyola 571 CL e Hyola 575 CL). Os hibridos Hyola 50 e Hyola 61 apresentaram os maiores subperiodos EIF, DFL, DMA e ciclo. Todavia, atrasar a epoca de semeadura reduziu os subperiodos de todos os hibridos. A maior produtividade foi obtida com Hyola 50, Hyola 61 e Hyola 433, respectivamente. A medida que atrasou a semeadura, houve reducao na massa de mil graos, produtividade e teor de oleo. Independente do hibrido, o melhor intervalo de semeadura foi entre 07/04 e 22/04 e as melhores respostas agronomicas foram obtidas pelos hibridos Hyola 50, Hyola 61 e Hyola 433.

The Atlantic spotted dolphin (Stenella frontalis) is endemic to tropical, subtropical, and warm temperate waters of the Atlantic Ocean. Throughout its distribution, both geographic distance and environmental variation may contribute to population structure of the species. In this study, we follow a seascape genetics approach to investigate population differentiation of Atlantic spotted dolphins based on a large worldwide dataset and the relationship with marine environmental variables. The results revealed that the Atlantic spotted dolphin exhibits population genetic structure across its distribution based on mitochondrial DNA control region (mtDNA-CR) data. Analyses based on the contemporary landscape suggested, at both the individual and population level, that the population genetic structure is consistent with the isolation-by-distance model. However, because geography and environmental matrices were correlated, and because in some, but not all analyses, we found a significant effect for the environment, we cannot rule out the addition contribution of environmental factors in structuring genetic variation. Future analyses based on nuclear data are needed to evaluate whether local processes, such as social structure and some level of philopatry within populations, may be contributing to the associations among genetic structure, geographic, and environmental distance.

Population structure studies play an increasingly integral role in conservation and management of marine mammal species. Genetic markers are commonly used; however, ecological markers (i.e. chemical compounds) are a fairly recent and useful tool to investigate ecological management units. The objective of this study is to investigate the population structure of the Atlantic spotted dolphin (Stenella frontalis) within its distribution in the Atlantic Ocean using data from stable isotopes of δ13C and δ15N and persistent organic pollutants as ecological markers. Based on previous studies that addressed distribution, morphometric analyses and molecular and ecological markers, we hypothesize that there are several ecological management units within the Atlantic Ocean. Our results confirmed population differentiation previously detected using genetic markers. Additionally, dolphins from the south-eastern coast of Brazil do not show complete ecological segregation from the Caribbean ones, while molecular analyses suggested genetic differentiation between the two regions. In the light of these results, we propose that at least two ecological management units should be considered, east and west of the Atlantic Ocean; however, the presence of one or two management units along the Atlantic coast of Central and South America needs further investigation.

International audience; Sperm whales are present along the Caribbean islands in family groups of mature females, juveniles, and newborns. Their abundance and demographic rates remain poorly known. Using photo-identification data, we estimated the abundance and annual survival of sperm whales in Guadeloupe from January to April 2001–2013. A total of 1,492 photographs of tail flukes were scored (ranging from 1 to 5) in terms of quality (Q) and marking (M) level. A total of 789 photographs were selected with Q ≥ 3 and M ≥ 3, corresponding to 109 individually identified adult females or immatures of both sexes. Capture histories were built and analyzed using the Pollock's robust design capture-mark-recapture model. The study consisted of 13 primary periods sequenced in 5–8 secondary periods. Mean annual survival rate of residents was 0.945, 95% CI [0.864, 0.979]. Abundance varied between years from 75 to 35 individuals. The geometric growth rate over the period 2001–2013 was 0.938, 95% CI [0.878, 0.997], suggesting a population decline of −6.2%/year. Sperm whales are moving between Guadeloupe and Dominica, with a high temporary emigration rate (0.163) and 50% of the individuals of Guadeloupe resighted in Dominica. These results highlight the fragility of the population and the necessity to consider it as one unit.

Killer whales Orcinus orca are found in all oceans of the world, but most of our knowledge on the species comes from studies conducted at higher latitudes. Studies on killer whales in the Caribbean have been scarce. We compiled 176 records of killer whales from the Caribbean, including 95 previously unreported records and 81 records recovered from the literature, consisting of 27 capture or kill records, 4 stranding records and 145 sighting records. Our results indicate that killer whales are widespread in the Caribbean Sea and can be found year-round in the region. Mean group size was 3.7 animals. A diversity of prey items was recorded, including sea turtles and marine mammals and possibly fish. We cannot exclude ecotype or morphotype-specific dietary specialization in the Caribbean population. A preliminary morphological analysis of 10 characters in 52 individuals from 21 different groups suggests that Caribbean killer whales do not represent any of the four Antarctic and subantarctic types, type 1 from the northwest Atlantic, or ‘resident’ and ‘transient’ killer whales from the northwest Pacific. Some Caribbean killer whales share a combination of characters typical of type 2 in the North Atlantic, whereas others share those typical of ‘offshore’ killer whales in the northwest Pacific. The significance of this is unclear. Comparison of Caribbean killer whales to previously described morphotypes and ecotypes is hampered by the lack of detailed, quantitative data on variation within other types, as well as by the lack of comparisons of genetic diversity. Our study adds to the growing knowledge of the diversity of killer whales worldwide but underscores that additional research is warranted in the tropics.

There is substantial geographic variation in the behavior and social structure of sperm whales worldwide. The population in the Eastern Caribbean is thought to be isolated from other areas in the North Atlantic. We describe the behavior and social structure of the sperm whales identified off Dominica during an eight year study (2005–2012; 92% of photographic identifications) with supplementary data collected from seven other organizations dating as far back as 1981. A total of 419 individuals were identified. Resighting rates (42% of individuals between years) and encounter rates with sperm whale groups (mean = 80.4% of days at sea) among this population were both comparatively high. Group sizes were small (7–9 individuals) and were comprised of just one social unit (mean = 6.76 individuals, SD = 2.80). We described 17 units which have been reidentified off Dominica across 2–27 yr. Mature males are seen regularly off Dominica, but residency in the area lasts only a few days to a few weeks. Males were reidentified across years spanning up to a decade. Management of this population within the multinational Wider Caribbean Region will require governments to work towards international agreements governing sperm whales as a cross-border species of concern.