Balaenoptera Bonaerensis Research Articles

Diverse baleen whale acoustic occurrence around two sub-Antarctic islands: A tale of residents and visitors

Knowledge on the occurrence and behaviour of baleen whales around sub-Antarctic regions is limited, and usually based on short, seasonal sighting research from shore or research vessels and whaling records, neither of which provide accurate and comprehensive year-round perspectives of these animals’ ecology. We investigated the seasonal acoustic occurrence and diel vocalizing pattern of baleen whales around the sub-Antarctic Prince Edward Islands (PEIs) using passive acoustic monitoring data from mid-2021 to mid-2023, detecting six distinct baleen whale songs from Antarctic blue whales, Madagascan pygmy blue whales, fin whales, Antarctic minke whales, humpback whales, and sei whales. Antarctic blue and fin whales were detected year-round whereas the other species’ songs were detected seasonally, including a new Antarctic minke whale bio-duck song sub-type described here for the first time. Antarctic minke and sei whales were more vocally active at night-time whereas the other species had no clear diel vocalizing patterns. Random forest models identified month and/or sea surface temperature as the most important predictors of all baleen whale acoustic occurrence. These novel results highlight the PEIs as a useful habitat for baleen whales given the number of species that inhabit or transit through this region.

Simulations of IDCR and SOWER Antarctic minke whale abundance surveys

The International Whaling Commission (IWC) conducted abundance line‐transect surveys of Antarctic minke whales (Balaenoptera bonaerensis) during the International Decade of Cetacean Research (IDCR) between 1978/79 and 2003/04. These surveys continued throughout 2004/05–2009/10 under the Southern Ocean Whale and Ecosystem Research (SOWER) programme. Several methods used to analyse these data resulted in very different abundance estimates. In order to evaluate the accuracy of these methods, the IWC Scientific Committee recommended using simulated line‐transect data. The software package TRANSIM was therefore modified to generate simulated line‐transect data that emulated an IDRC/SOWER survey in a study area populated with whales that followed the distribution, density and behaviour of Antarctic minke whales. Simulations incorporated factors that could potentially bias resulting abundance estimates, and in order to investigate the effects of these factors on the resulting abundance estimates, simulated datasets were generated for different scenarios, each of which incorporated combinations of factors that were chosen using the mirror‐image fold‐over partial factorial method that is designed to identify factors related to biased estimates. This paper describes the programme used to generate these datasets and reports on the robustness of the statistical methods applied to analyse them. In addition, a brief discussion is included on how this information was used when the actual line‐transect data were analysed. The statistical methods investigated were the hazard probability method (OK), integrated hazard probability method (IM), spatial point independence method (SPL) and standard method. After developers analysed the simulated data, they used this information to improve their analytical methods. The results reported here focus on the performance of the most advanced versions of the OK and SPL methods compared with the standard method as of 2009. In general, SPL estimates of group density were negatively biased, OK estimates were positively biased, standard estimates were the most negatively biased and IM estimates were the least biased. Density estimates from SPL were less biased than estimates from OK in the complex scenarios that contained spatial gradients and correlations between density, location and weather conditions. The OK method was less robust when: (1) closing‐mode data collection procedures were simulated; (2) whale groups were diving in a non‐synchronous fashion; and (3) there were complex spatial patterns. In almost every case, the density estimates from the OK method were greater than the SPL methods, on average by 10–15%. These observations assisted the development of more robust analysis methods and highlighted which factors should be addressed when analysing the actual data.

The SOWER programme in the Antarctic: Background, aims and objectives

The International Whaling Commission (IWC) imposed limits on the catch of Antarctic minke whales close to the start of commercial whaling in the 1970s. These management efforts were hampered by the challenge of obtaining robust estimates of population size. Contemporary whale assessments largely relied on measuring changes in availability as a result of exploitation – usually catch per unit effort (CPUE). However, this approach was largely impractical for Antarctic minke whales due to: (a) the short time series of CPUE data; (b) the setting of relatively conservative catch limits, so that changes in CPUE due to exploitation were difficult to detect; and (c) the possibility that abundance had been increasing before this time due to over‐exploitation of other baleen whales. The IWC initiated a series of assessment cruises in 1978 designed to obtain abundance estimates for targeted management areas in the Antarctic. Designed by the IWC’s Scientific Committee, these cruises were independent of whaling operations. The vessels were chartered whale catchers provided by Japan for the duration of the programme – and by the Soviet Union for a period of seven years. With the eventual participation of 86 scientists from 16 IWC member states, this programme became a key part of the International Decade of Cetacean Research (IDCR), launched in 1975 as a response to the 1972 Stockholm Resolution that called for a 10‐year moratorium on commercial whaling and the intensification of research efforts. While originally planned as ‘Discovery’ marking and sighting cruises, the programme eventually relied almost exclusively on sighting methods. Lasting over 30 years and involving three circumnavigations of the Southern Ocean, it became one of the largest whale monitoring exercises ever undertaken.

Antarctic Minke Whale (Balaenoptera bonaerensis) Bio-Duck Call Detection in the Río de la Plata, Uruguay

Passive acoustic monitoring (PAM) has become a popular method for studying both marine mammal behavior and distribution, especially among cetaceans. The Antarctic minke whale (Balaenoptera bonaerensis) occurs in the Southern Hemisphere, and our knowledge concerning its vocal behavior is very limited. Along the coast of Uruguay, minke whales constitute one of the species with the most stranding data collected. Until now, sounds of Antarctic minke whales had never been recorded off the Uruguayan coast. Two different bio-duck call types were recorded along the Atlantic Ocean and the Río de la Plata River coasts by employing PAM stations off the coast of Uruguay in five different positions. One call was recorded off the Atlantic coast, and the four other calls were recorded along the Río de la Plata River, including the classic bio-duck call. In addition to the aforementioned bio-duck call, evidence of a novel call, the bio-duck pulse train, was found. This call was produced in an environment very different from the oceanic environment. The bio-duck pulse train has never been described in previous works, making the findings of the present work all the more novel.

Killer whale predation on an Antarctic minke whale in the northern Antarctic Peninsula.

We describe the seldom observed event of a group of type A killer whale (Orcinus orca) predating on an Antarctic minke whale (Balaenoptera bonaerensis) in austral summer 2019. A pod of 11-13 individuals was observed - and documented by photographs and video - as they killed and fed on the minke whale in the Bransfield Strait, northern Antarctic Peninsula. The pod was being observed for about one hour, when some killer whale's individuals were noticed to be performing hunting behaviour. This lasted about 10 minutes, at the end of which the minke whale was killed. Three different species of seabirds were observed feeding on the minke carcass. A video of the encounter is provided.

Species Composition and Distribution of Cetaceans in the Atlantic and Indian Sectors of Southern Ocean

The data of accompanying observations of the spatial distribution, species composition and abundance of cetaceans in the southern part of the Atlantic and Indian oceans and in the coastal waters of Antarctica in the southern autumn of 2021 are presented. In total, 3 species of whales (82 sightings–136 individuals), 1 species of beaked (1 sighting–4 individuals) and 6 species of dolphins (15 sightings–324 individuals) were registered in the research area. In total, cetacean were observed 98 times, 464 individuals were registered. As in previous years, humpback whales Megaptera novaeangliae predominated (58.82%), they are successfully restoring their quantity, although they suffered greatly during whaling in the XVIII–XX centuries. Antarctic minke whales Balaenoptera bonaerensis made up 21.32%, and fin whales Balaenoptera physalus made up 19.85% of all whales. Southern right whale dolphins (83.33%) prevailed among all dolphins.

Overview of Balaenoptera whales strandings in Southern Brazil from 1993 to 2018

The ecology and distribution of most baleen whales are poorly known in Brazilian waters, despite the history of whaling and the recent increase in the research effort. Although stranding data presents some caveats, it is useful to understand patterns of distribution and occurrence and to detect population trends. In this scenario, data from 25 years of a monitoring marine mammal stranding program were used to evaluate the composition and spatial-temporal patterns of Balaenoptera whales in southern Brazil. A stretch of 270 km on the coast of Rio Grande do Sul State (from 29°20’S to 31°21’S) was surveyed year-round between 1993 and 2018. Whales were identified, measured and sex determined whenever possible. Molecular identification through mtDNA analysis was obtained for 22 individuals and confirmed field identification in 17 cases. Forty-eight whales of four species were recorded: common minke whale B. acutorostrata n = 27, Antarctic minke whale B. bonaerensis n = 1, Bryde’s whale B. brydei n = 13, fin whale B. physalus n = 1. In addition, six whales were not identified at species level due to advanced decomposition. The larger number of strandings of common minke and Bryde’s whales may be related to their greater abundance and/or more coastal distribution. Both species were recorded year-round, but strandings of common minke and Bryde’s whales occurred mostly during winter/spring (77.77%) and spring/summer (66.66%), respectively. Although Bryde’s whales appear to remain in southern Brazilian waters during the entire year, the results suggest the existence of seasonal inshore-offshore movements. Moreover, the greater number of strandings of juveniles of common minke whales compared to adults (ratio 1.86:1) and their occurrence in different seasons suggest that some immature individuals may not leave this region, as previously pointed out by other studies. This long-term survey brings new evidence of the importance of this region in the Southwestern Atlantic Ocean for some Balaenoptera species.

Spatial and temporal variability of the acoustic repertoire of Antarctic minke whales (Balaenoptera bonaerensis) in the Weddell Sea

Since the attribution of the bio-duck call to Antarctic minke whales (AMW Balaenoptera bonaerensis), different studies have retrospectively identified several bio-duck call types at various sites throughout the Southern Hemisphere. The function of their vocal behavior however, remains largely unknown. Further insights into their repertoire usage may help to reveal the function of their calls. Here, we use passive acoustic monitoring (PAM) data collected across six locations throughout the Weddell Sea (WS) in 2013 and from PALAOA Station (Ekström Ice Shelf, eastern WS) in 2015, 2016 and 2017. In 2013, we detected 11 bio-duck call types throughout the WS between May and December, with additional acoustic activity in February on the western recorder AMW calls fell into four general call clusters. Seasonal patterns of calls showed variability between locations and years. Furthermore, this is the first study to show that similar to other baleen whale species, AMWs also produce songs.

Estimates of abundance south of 60°S for cetacean species sighted frequently on the 1978/79 to 1997/98 IWC/IDCR-SOWER sighting surveys

Estimates of abundance are calculated for six cetacean species in the Southern Ocean south of 60° in the austral summer, using the IWC database estimation package (DESS). The sightings data in DESS were collected during the 1978/79 to 1997/98 IWC/IDCR and SOWER circumpolar surveys. Abundance estimates are developed for the first (1978/79–1983/84), second (1985/86–1990/91) and currently incomplete third (1991/92–1997/98) circumpolar sets of surveys. The strata surveyed in these three sets cover about 65%, 81% and 68% respectively of the open ocean area south of 60°S. The surveys were designed for Antarctic minke whales and may not be optimal for all these species. Furthermore, the estimates presented below (CVs in brackets) should not necessarily be considered as estimates for the whole Southern Hemisphere. Some results are also presented for hourglass dolphins and sei whales, but estimates of abundance are not considered reliable for those two species. Effective search half-width and mean school size were estimated by pooling across strata and years. Pooling is effected separately for each circumpolar set of surveys. Additional pooling across closing and passing modes did not introduce substantial bias. The most frequently sighted species were minke, southern bottlenose, sperm, humpback and killer whales; the effective search half-widths for all five increase over time. The sensitivity of the abundance estimates to a number of factors is investigated, none of which appears to impact the results substantially, except that the incorporation of ‘like species’ would increase the estimate for blue whales from the third circumpolar set of surveys by 25% and for fin whales by 61%. In general, the assumption that 100% of schools on the trackline are sighted introduces variable negative bias to estimates for all species. Only two significant trends in abundance over time (for comparable areas) were detected, but both may be artefacts of changes in survey design.

Errors in age estimates of North Atlantic minke whales when counting growth zones in bulla tympanica

Age estimation of common minke whales (Balaenoptera acutorostrata) has always been difficult, and the accuracy of the current method of counting growth layer groups (GLGs) in the periosteal zone of the tympanic bulla has been questioned. To evaluate this method, two readers aged three sections from each of right and left bulla tympanica from 35 male and 57 female North Atlantic minke whales. A single age estimate with variance was calculated for each whale using General Linear Mixed Model Poisson based regression, and this estimate was compared with the number of ovulations and body length to evaluate the bias of the age determination method. The results showed a poor fit between age and number of ovulations with R2 = 0.0014. Bias was estimated to be a 37% underestimate of ‘true’ age assuming an ovulation rate of one per year and age at sexual maturity of eight years. Precision of the bulla age estimates was lower than those of Antarctic minke whales aged using the earplug method. The high bias reduces the applicability of the bulla method in routine age-determination with a management objective. Other age determination methods for the species should be improved or developed to ensure proper monitoring of demography and life history for the North Atlantic minke whale.

Observer experience and Antarctic minke whale sighting ability in IWC/IDCR-SOWER surveys

The relationship between observer experience and the number of minke whale schools sighted on International Whaling Commission/International Decade of Cetacean Research-Southern Ocean Whale and Ecosystem Research (IWC/IDCR-SOWER) surveys from 1993/94 to 1998/99 is investigated for Independent Observer (IO) mode survey. Observer experience is defined as the number of past sightings surveys in which the observer participated. During the third circumpolar set of surveys (from 1991/92 onwards), about half of the observers had participated in fewer than five previous sightings surveys. Based upon the QAIC model selection criterion, the observers are classified into two groups depending on their experience: ‘Beginners’ (0-4 surveys) and ‘Experts’ ( > 4). The sighting rate for minke whale schools by Beginners is estimated to be 42% lower than that by Expert observers. Furthermore, perpendicular distances to the sightings do not show significant differences in relation to observer experience. These results jointly indicate that the probability of detection on the trackline, g(0), may be less than one when Beginners are amongst those observing. Abundance estimation for minke whales in IO mode involves the sightings made by triple observer combinations, with two observers in the barrel and one observer in the Independent Observer Platform (IOP) all searching simultaneously. Surprisingly, given the result above, no significant trend in sighting rate with the combined experience of this three-observer combination is detected. This might be an artifact of small sample size for some observer combinations, such as Experts in all platforms. When observer combinations in the barrel are pooled across, the estimated trend in the sighting rate with combined observer experience becomes steeper. Furthermore, when like-minke sightings are also taken into account, the trend becomes steeper still. In this case, when observations are pooled across observer combinations in the barrel, a model for sighting rate that includes an observer effect is selected in terms of the QAIC criteria. These analyses thus provide suggestive evidence that the introduction of Beginner observers during the third circumpolar set of surveys may have reduced g(0) and hence negatively biased abundance estimates for minke whales, both in absolute terms and compared with estimates from the second circumpolar set of surveys.

Three forms of killer whales (Orcinus orca) in Antarctic waters

This paper provides field descriptions and biological observations of three different forms of killer whale (Orcinus orca) that occur in Antarctica based on field observations and a review of available photographs. Identifications were based on the relative size and orientation of the white eyepatch and the presence or absence of a dorsal cape. Type A (presumably the nominate form) has a medium-sized eyepatch oriented parallel to the body axis, no dorsal cape, it occurs mainly off-shore in ice-free water, has a circumpolar distribution and apparently preys mainly upon Antarctic minke whales (Balaenoptera bonaerensis). Type B also has an eyepatch oriented parallel to the body axis, but the eyepatch is at least twice as large as in Type A, it has a dorsal cape, mainly inhabits inshore waters, regularly occurs in pack-ice, is distributed around the continent and is regularly sighted in the Antarctic Peninsula area. Although it may also prey upon Antarctic minke whales and possibly humpback whales (Megaptera novaeangliae), seals seem to be the most important prey item. Type C has a small, forward-slanted eyepatch, a dorsal cape, inhabits inshore waters and lives mainly in the pack-ice; it occurs mostly off East Antarctica, and to date it has been recorded feeding only on Antarctic toothfish (Dissostichus mawsoni). Type C appears to be referable to Orcinus glacialis as described by Berzin and Vladimirov (1983). Although similar ecological specialisations have been reported for sympatric killer whale populations in the Northeast Pacific (i.e. an inshore mammal-eater, an inshore fish-eater and an offshore form), the extent of morphological divergence, habitat segregation and, perhaps, reproductive isolation, appears to be more pronounced among Antarctic populations. Although under a Biological Species Concept these forms appear to warrant separate species status, it will be important to show that this interpretation is consistent with results of molecular genetic analyses and additional morphological studies.

Yasunaga et al. (2022) meets the ethics code of Marine Mammal Science, and the journal's decision to publish the paper is correct

Yasunaga et al. (2022) meets the ethics code of <i>Marine Mammal Science</i>, and the journal's decision to publish the paper is correct

An improved method for line transect sampling in Antarctic minke whale surveys

The series of abundance estimates for Antarctic minke whales obtained using standard line transect methods from IWC/SOWER surveys imply drastic (and probably unrealistic) changes in true abundance. One possible factor is that the detection probability on the trackline, g(0), may have decreased with the introduction of inexperienced observers in the most recent surveys. Additionally, mean observed school size may have decreased in the third circumpolar survey in comparison with the second survey. This paper introduces an extended and generalised hazard probability model without the assumption that g(0)=1 to estimate true school size distribution in the population. The proposed method uses a survey design that combines the use of both passing mode with independent observers and closing mode in which the vessel turns off the trackline and closes with the sighting for confirmation of school size and species. The abundance estimate is based on the Horvitz-Thompson estimator in an unequal detectability sampling scheme. The method is applied to the IDCR/SOWER dataset of Antarctic minke whales for illustrative purposes.

Effects of observed covariates (school size, sighting cue, latitude and sea state) on the Antarctic minke whale abundance estimation parameters in the IWC/IDCR-SOWER surveys

The effects of observed covariates (school size, sighting cue, latitude and sea state) on Antarctic minke whale abundance estimation parameters (effective search half-width, sighting forward distance and mean school size) were examined qualitatively. As the school size decreased, the effective search half-width and the sighting forward distance decreased. Most single and two animal schools were sighted by body, which was difficult in high sea states in comparison with those sighted by blow. Proportions of single and two animal schools increased as sighting latitude moved north. Small school sizes and bad weather conditions prevailed in the northern part of the survey area. As the survey area was extended to the north, the effects of small school size and bad weather conditions could be substantial in the third circumpolar survey. Observed covariates analysed in this paper should be incorporated into the estimation of effective search half-width and mean school size as covariates.

Minke whale feeding rate limitations suggest constraints on the minimum body size for engulfment filtration feeding.

Bulk filter feeding has enabled gigantism throughout evolutionary history. The largest animals, extant rorqual whales, utilize intermittent engulfment filtration feeding (lunge feeding), which increases in efficiency with body size, enabling their gigantism. The smallest extant rorquals (7-10 m minke whales), however, still exhibit short-term foraging efficiencies several times greater than smaller non-filter-feeding cetaceans, raising the question of why smaller animals do not utilize this foraging modality. We collected 437 h of bio-logging data from 23 Antarctic minke whales (Balaenoptera bonaerensis) to test the relationship of feeding rates (λf) to body size. Here, we show that while ultra-high nighttime λf (mean ± s.d.: 165 ± 40 lunges h-1; max: 236 lunges h-1; mean depth: 28 ± 46 m) were indistinguishable from predictions from observations of larger species, daytime λf (mean depth: 72 ± 72 m) were only 25-40% of predicted rates. Both λf were near the maxima allowed by calculated biomechanical, physiological and environmental constraints, but these temporal constraints meant that maximum λf was below the expected λf for animals smaller than ~5 m-the length of weaned minke whales. Our findings suggest that minimum size for specific filter-feeding body plans may relate broadly to temporal restrictions on filtration rate and have implications for the evolution of filter feeding.

A note on the first record of the dwarf minke whale (Balaenoptera acutorostrata) in Chilean waters

Two species of minke whale have been recognised, the larger Antarctic minke whale (Balaenoptera bonaerensis) restricted to the Southern Hemisphere, and the common minke whale (B. acutorostrata), which is distributed globally. The common minke whale of the Southern Hemisphere is referred to as the dwarf minke whale. The occurrence and identity of minke whales in the coastal waters of Chile are examined based on animals stranded and sighted in the Patagonia Channels. A total of three strandings and five sightings of the minke whale were examined in this study. Comparative analysis of external characteristics between the stranded animals and the two recognised species of minke whale identified these animals as dwarf minke whales. Of the five sightings, two were identified as Antarctic and two as dwarf minke whales based on observation of the presence/absence of the white patch on the flippers. This is the first record of the dwarf minke whale in the coastal waters of Chile. Based on available information on temporal distribution of sightings in the western south Atlantic, it is suggested that the population of dwarf minke whales wintering off Brazil may move to the south in summer, some moving into the Patagonia Channels.

Baleen whales in the Scotia Sea during January and February 2003

Different species of baleen whales display distinct spatial distribution patterns in the Scotia Sea during the austral summer. Passive acoustic and visual surveys for baleen whales were conducted aboard the RRS James Clark Ross in the Scotia Sea and around South Georgia in January and February 2003. Identified calls from four species were recorded during the acoustic survey including southern right (Eubalaena australis), blue (Balaenoptera musculus), fin (B. physalus) and humpback whales (Megaptera novaeangliae). These acoustic data included up calls made by southern right whales, downswept D and tonal calls by blue whales, two possible types of fin whale downswept calls and humpback whale moans and grunts. Visual detections included southern right, fin, humpback and Antarctic minke whales (B. bonaerensis sp.). Most acoustic and visual detections occurred either around South Georgia (southern right and humpback whales) or south of the southern boundary of the Antarctic Circumpolar Current (ACC) and along the outer edge of the ice pack (southern right, blue, humpback and Antarctic minke whales). Fin whales were the exception, being the only species acoustically and visually detected primarily in the central Scotia Sea, along the southern ACC front. In addition to identifiable calls from these species, two types of probable baleen whale calls were detected: 50Hz upswept and pulsing calls. It is proposed that minke whales may produce the pulsing calls, based on their similarities with minke whale calls recorded in the North Atlantic Ocean. There was an overlap between locations of fin whale sightings and recordings and locations of 50Hz upswept calls in the central Scotia Sea, but these calls were most similar to calls attributed to blue whales in other parts of Antarctica. More study is required to determine if baleen whales produce these two call types, and if so, which species. The efficiency of acoustics and visual surveys varied by species, with blue whales being easier to detect using acoustics, Antarctic minke whales being best detected during visual surveys and other species falling in between these two extremes.

Sightings of Cetaceans during JARE - 56 in the Indian Sector of the Southern Ocean

The cetacean observation was made during the 56th Japanese Antarctic Research Expedition (JARE - 56) cruise on the icebreaker SHIRASE, from 30 November to 15 December 2014 and from 15 February to 9 March 2015, in the Indian Ocean Sector of the Southern Ocean. A total of 28 sightings with 64 individuals of four cetacean species, humpback whale, (Megaptera novaeangliae), fin whale (Balaenoptera physalus), Antarctic minke whale (Balaenoptera bonaerensis), and killer whale (Orcinus orca), are reported. The most sighted species was the humpback whale (13 sightings) and the maximum number of individuals in a group was six for the same species. All sightings were made higher than 60 degrees South, close to the Antarctica coast.

Assessing the viability of estimating baleen whale abundance from tourist vessels

Many populations of southern hemisphere baleen whales are recovering and are again becoming dominant consumers in the Southern Ocean. Key to understanding the present and future role of baleen whales in Southern Ocean ecosystems is determining their abundance on foraging grounds. Distance sampling is the standard method for estimating baleen whale abundance but requires specific logistic requirements which are rarely achieved in the remote Southern Ocean. We explore the potential use of tourist vessel-based sampling as a cost-effective solution for conducting distance sampling surveys for baleen whales in the Southern Ocean. We used a dataset of tourist vessel locations from the southwest Atlantic sector of the Southern Ocean and published knowledge from Southern Ocean sighting surveys to determine the number of tourist vessel voyages required for robust abundance estimates. Second, we simulated the abundance and distributions of four baleen whale species for the study area and sampled them with both standardized line transect surveys and non-standardized tourist vessel-based surveys, then compared modeled abundance and distributions from each survey to the original simulation. For the southwest Atlantic, we show that 12-22 tourist vessel voyages are likely required to estimate abundance for humpback and fin whales, with relative estimates for blue, sei, Antarctic minke, and southern right whales. Second, we show tourist vessel-based surveys outperformed standardized line transect surveys at reproducing simulated baleen whale abundances and distribution. These analyses suggest tourist vessel-based surveys are a viable method for estimating baleen whale abundance in remote regions. For the southwest Atlantic, the relatively cost-effective nature of tourist vessel-based survey and regularity of tourist vessel voyages could allow for annual and intra-annual estimates of abundance, a fundamental improvement on current methods, which may capture spatiotemporal trends in baleen whale movements on forging grounds. Comparative modeling of sampling methods provided insights into the behavior of general additive model-based abundance modeling, contributing to the development of detailed guidelines of best practices for these approaches. Through successful engagement with tourist company partners, this method has the potential to characterize abundance across a variety of marine species and spaces globally, and deliver high-quality scientific outcomes relevant to management organizations.