New England Aquarium

In species with prolonged parental investment, extended care imposes considerable costs. In Northern Resident killer whales (Orcinus orca), maternal investment is demanding due to long gestation, extended lactation, and lifelong care of non-dispersing offspring. Using 10 years of aerial images, we assessed whether reproduction and maternal care affected body condition in 66 reproductive-aged females. Females in late pregnancy had significantly higher body condition than those not pregnant or with unsuccessful pregnancies, while females in the first two years of lactation had significantly lower condition. By year three, body condition rebounded, coinciding with weaning. To evaluate long-term costs, we analyzed body condition in 75 adult females relative to: (1) number of living offspring (life-long parental care hypothesis), (2) lifetime births (successive reproduction hypothesis), and (3) number of living sons (expensive sons hypothesis), while accounting for prey abundance. Maternal condition declined with increasing numbers of living offspring and lifetime births, independent of Pacific Salmon Commission Chinook salmon (Oncorhynchus tshawytscha) abundance index. Living offspring was the strongest predictor of the reproductive history covariates, supporting the life-long parental care hypothesis. We found no support for the expensive sons hypothesis. These findings highlight energetic costs of extended maternal investment in long-lived, socially complex species.

Aquitanian pike, Esox aquitanicus , is a new esocid species described in 2014 and endemic to Southwestern France. The four main goals of the present study were to (i) obtain the first morphological data on the early life stages, (ii) test the effects of temperature on their survival and development, (iii) compare the results with the Northern pike, and (iv) produce a few individuals to exhibit them at the Aquarium of Limoges. Eggs are yellowish, demersal, and sticky. The mean diameter was 2.73 ± 0.08 mm ( n = 174). The larval size at hatching was 9.09 ± 0.24 mm ( n = 14). The morphological development of 15 larvae was followed during 11 weeks as well as the snout growth in relation to eye size. It appeared that already after three weeks, slight differences between the two species were apparent, and after nine weeks, this snout/eye ratio was twice greater for Northern pike than Aquitanian pike. At the end of the yolk-feeding period, which lasted from 12 days at 18 °C to 36 days at 6 °C, the overall survival rate was over 85% and larvae were of similar size, except at 6 °C. After three months, the best results in term of survival were obtained at 12 °C (60%) and for growth at 15 °C (34.11 mm), followed at 12 °C (27.85 mm). Based on these results, we were able to rear Aquitanian pike for more than 2 years in the Aquarium of Limoges in order to promote the conservation of the species to the public.

Long term studies in ecology and biology have been essential for addressing significant evolutionary and ecological questions. Long term marine mammal studies face different challenges, but are proving critical to ocean policy. New technologies combined with long term marine mammal studies provide important information on trends in population biology, anthropogenic stressors, climate change, and oceanographic regime shifts.

To document surgical incision healing for hospitalized sea turtles. Medical records for sea turtle surgical cases from a single hospital between 2008 and 2024 were retrospectively evaluated. Cases that involved traumatic wounds or open fractures that were present at the time of admission, ophthalmic surgery, or acoustic transmitter implantations were excluded. Species, weight, time since admission to the hospital, surgical procedure, methods, duration, temporal proximity of diagnostic testing and antibiotic use, and presence of major comorbidities were evaluated as related to healing duration and complication occurrence. Complicated incisions were defined as those that required substantial additional medical or surgical management to promote healing. 48 Kemp's ridley turtles (Lepidochelys kempii) and 4 loggerhead turtles (Caretta caretta) had 70 surgical incisions. Fifty-five incisions for 38 turtles healed, while 14 turtles (15 incisions) died prior to healing. Complications occurred in 20% of the 55 incisions. Orthopedic surgical incisions had a higher complication rate (37.5%) compared to soft tissue surgical incisions (6.5%). Complicated incisions had longer healing duration (mean ± SD, 74 ± 25 days; median, 75 days; range, 40 to 113 days) compared to uneventful incisions (mean ± SD, 41 ± 13 days; median, 39 days; range, 20 to 81 days). Body weight was positively associated with healing duration. Although the use of suture instead of staples for skin closure was positively associated with complications, this may have been related to nature of the surgery (orthopedic vs soft tissue) rather than the skin closure method. Sea turtle surgical incisions have a moderately high rate of complications, especially for orthopedic procedures. Complications may not be apparent for several weeks, but they can be successfully managed. Incisions generally heal within several months, even if complicated. Given the complication rate in the present study, careful postoperative monitoring is recommended for several months following surgery in sea turtles, and additional management may be needed in cases with complications.

Abstract Background Reference genomes for the entire sea turtle clade have the potential to reveal the genetic basis of traits driving the ecological and phenotypic diversity in these ancient and iconic marine species. Furthermore, these genomic resources can support conservation efforts and deepen our understanding of their unique evolution. Results We present haplotype-resolved, chromosome-level reference genomes and high-quality gene annotations for five sea turtle species. This completes the catalog of reference genomes of the entire sea turtle clade when combined with our previously published reference genomes. Our analysis reveals remarkable genome synteny and collinearity across all species, despite the clade’s origin dating back more than 60 million years. Regions of high interspecific genetic distance and intraspecific genetic diversity are consistently clustered in genomic hotspots, which are enriched with genes coding for immune response proteins, olfactory receptors, zinc fingers, and G-protein-coupled receptors. These hotspot regions may offer insights into the genetic mechanisms driving phenotypic divergence among species, and represent areas of significant adaptive potential. Ancient demographic analysis revealed a synchronous population expansion among sea turtle species during the Pleistocene, with varying magnitudes of demographic change, likely shaped by their diverse ecological adaptations, and biogeographic contexts. Conclusions Our work provides genomic resources for exploring genetic diversity, evolutionary adaptations, and demographic histories of sea turtles. We outline genomic regions with increased diversity, linked to immune response, sensory evolution, and adaptation to varying environments that have historically been subject to strong diversifying selection, and likely will underpin sea turtle’s responses to future environmental change. These reference genomes can assist conservation by providing insights into the demographic and evolutionary processes that sustain and threaten these iconic species.

To develop safe and effective management policies, it is important to understand the physiologic effects of fishing interactions and scientific research methods on endangered marine species. In the present study, validated assays for plasma corticosterone, free thyroxine (fT4), and aldosterone were used to assess the endocrine status of 61 presumed healthy, wild Kemp's ridley sea turtles (Lepidochelys kempii) that were captured for separate ecological studies using two capture methods (trawl net n = 40; manual capture n = 21). Plasma hormone concentrations were also assessed in relation to eight clinical plasma biochemical analytes. Corticosterone and aldosterone concentrations were moderately high after capture, with significantly higher concentrations in turtles captured by trawl net vs. manual capture. Free thyroxine concentrations were within previously published ranges for healthy individuals of this species. Clinical biochemical data revealed moderately elevated potassium and lactate concentrations in many individuals, with significantly greater lactate concentrations in trawl-captured turtles. Aldosterone concentrations were positively correlated with corticosterone. The results of the present study indicate that Kemp's ridley sea turtles have robust adrenocortical activity immediately after capture, resulting in high plasma concentrations of corticosterone and aldosterone. Researchers who use such methods to access sea turtles can consider these results in planning careful and efficient field studies.

ABSTRACT The expansion of offshore wind interests in US waters has raised concern over potential adverse impacts to fisheries activity and productivity. Yet evidence‐based platforms for assessing those impacts are lacking for many recreational fisheries. We demonstrate how data from a federal fishery survey (Large Pelagics Intercept Survey [LPIS]), cooperative tagging programs, and the direct survey of recreational fishermen can be used to characterize the spatial extent of baseline (pre‐construction) effort in a recreational fishery that targets highly migratory fishes (HMS) in US territorial waters of the Atlantic, Gulf of Mexico, and Caribbean. To document the location of effort, LPIS catch data and tag, release, and recapture (CTR) records from four cooperative tagging programs were independently aggregated onto a grid of offshore wind lease blocks. An online survey of recreational fishermen was also executed to assess the spatial extent of effort in relation to a Draft Call Area (DCA) in the Gulf of Maine region. Collectively, the LPIS and CTR data described widespread recreational fishing effort for HMS, including within and around the majority of existing and planned offshore wind lease areas. Responses to the online survey revealed more widespread effort within the Gulf of Maine DCA than both the LPIS and CTR data, but some respondents may have overrepresented true levels of fishing effort. Our results demonstrate the need for multiple data types to comprehensively assess offshore wind impacts on the recreational HMS fishery and to inform marine spatial planning in regions into which offshore wind energy development may be expanded.

The scalloped hammerhead Sphyrna lewini and the great hammerhead S. mokarran are large, coastal to semi-oceanic shark species common to waters of the US east coast where they are regularly taken in commercial and recreational fisheries, particularly the bottom longline fishery. High rates of hooking mortality and low rates of population growth are believed to have caused severe declines in the US Atlantic populations of these species. The objective of this study was to determine the physiological stress induced by bottom longline capture in both S. lewini and S. mokarran. Physiological stress was quantified using the blood biochemical indicators glucose, lactate, pH, haematocrit, sodium, potassium, calcium, chloride and magnesium, which have been demonstrated to indicate physiological stress in elasmobranchs. Each shark captured was assigned a condition factor, which was compared with the stress parameters and time on hook to quantify stress induced by different longline hook times. In S. lewini, the physiological stress parameters lactate, pH, sodium and chloride scaled with hook time, whereas in S. mokarran, only lactate was affected by hook time. In both species, water temperature affected lactate and glucose levels, as well as sodium and pH levels in S. lewini and magnesium levels in S. mokarran. These data will be useful for estimating post-release mortality of S. lewini and S. mokarran from measurements taken at the time of capture, and quantifying the physiological stress response to longline capture in both species to the Atlantic bottom longline fishery.

ABSTRACTThe reduced genetic diversity and frequent inbreeding associated with small population size may underpin the accumulation and expression of deleterious mutations (mutation load) in some declining populations. However, demographic perturbations and inbreeding coupled with purifying selection can also purge declining populations of deleterious mutations, leading to intriguing recoveries. To better understand the links between deleterious genetic variation and population status, we assess patterns of genetic diversity, inbreeding, and mutation load across the genomes of three species of Balaenidae whale with different demographic histories and recoveries following the end of commercial whaling in the 1980s. Unlike bowhead (BH) and Southern right whales (SRW), which show signs of recent recovery, reproductive rates of the endangered North Atlantic right whale (NARW) remain lower than expected. We show that the NARW is currently marked by low genetic diversity, historical inbreeding, and a high mutation load. Still, we reveal evidence that genetic purging has reduced the frequency of highly deleterious alleles in NARW, which could increase chances of future population recovery. We also identify a suite of mutations putatively linked to congenital defects that occur at high frequencies in nulliparous NARW females but are rare in NARW with high reproductive success. These same mutations are nearly absent in BH and SRW in this study, suggesting that the purging of key variants may shape the probability of population recovery. As anthropogenic disturbances continue to reduce the sizes of many populations in nature, resolving the links between population dynamics and mutation load could become increasingly important.

Critically endangered North Atlantic right whales Eubalaena glacialis have recently shifted their summer distribution from the Bay of Fundy to the Gulf of St. Lawrence (GSL), Canada. Entanglement in fishing gear and vessel strikes remain the main lethal threats. Foraging on deep aggregations of Calanus prey in the Bay of Fundy involves stereotyped deep ‘flat-bottom’ (U-shaped) dives, while foraging on sub-surface Calanus aggregations on the winter feeding grounds of Cape Cod Bay involves surface feeding. To explore North Atlantic right whale feeding behaviour in the GSL, 5 acoustic and biologging tags (DTAGs) were deployed using suction cups in 2019 and 2020. One whale knocked off the tag after 14 min. Diving behaviour of the other 4 whales with 2.0 to 4.7 h of data was mostly split between flat-bottom foraging dives at, or very close to, the sea floor, and near-surface activities, including logging, respirations, and potentially also sleeping. This biphasic vertical distribution not only places the whales at risk of being hit by vessels, but it may also put them at risk of coming into contact with groundlines used in various fishing industries in the GSL. Although additional research is needed as this limited dataset was restricted to hours of daylight, these results provide new information about right whale behaviour in the GSL that can help inform management actions to reduce human impacts on this endangered species.