Humpback whales in Banderas Bay, Mexico: relative abundance and temporal patterns between 2004 and 2017

Banderas Bay, Mexico is an important breeding and transit area for the North Pacific humpback whale (Megaptera novaeangliae) population. In this paper we estimated relative abundance (RA = number of whales/hours of navigation) as a proxy to assess population temporary patterns in the area. We analyzed data from 14 breeding seasons (2004-2017), collected between December and March each winter. A total of 8,013 whales were observed in 1,394.6 navigation hours. Average seasonal RA was 5.7 whales per hour with a maximum of 7.5 (2013) and a minimum of 4.0 (2016). Sea surface temperature (SST) averaged 25.1°C and remained within the range considered optimal for humpback whale reproduction areas. SST showed no significant correlation with RA (r = 0.183). Inter-seasonal RA values suggested an increase throughout the study period, although the increase was not statistically significant (R = 0.32; R2 = 0.10; t = 1.15, p > 0.05). Intra-seasonal analyses showed that RA in December and January were significantly higher (U = 150, p < 0.05) than in February and March; this pattern was consistent throughout the seasons of study. These results represent a shift in the intra-seasonal abundance peak relative to previous studies when most whales were observed between January and February. It is important to recognize changes in population parameters of humpback whales in breeding areas to improve management practices. This study also highlights the potential of opportunistic platforms, such as whale watching tour boats, as viable sources of quality information, particularly in contexts when funding is limited.

Guidelines for collection of biological samples for giant otters (Pteronura brasiliensis Gmelin, 1788) and Neotropical otters (Lontra longicaudis Olfers, 1818)

To optimize the health evaluation of Giant and Neotropical otters in the wild and under human care and to guarantee the quality of the information collected and maximize efforts in research projects, Brazilian veterinarians developed two protocols: 1) Protocol for collection, processing and storage of biological samples from live Giant and Neotropical otters, 2) Protocol for collection of biological material during necropsy.

Cetacean community off French Guiana

Although human activities are developing in French Guiana Exclusive Economic Zone (EEZ) and surrounding countries, knowledge on diversity and ecology of cetaceans in the region is scarce. This study aimed to collect new information on the cetacean species occurring year-round in the entire French Guiana EEZ by combining visual and acoustic data obtained from three boat-based campaigns conducted by local NGOs. The GEPOG campaign was conducted from July 2011 to June 2012, four days every two months; the COHABYS campaign was performed five days per month from January to May 2018; the OSL campaign consisted in four 10-day surveys conducted in June, July, September and October 2018. The visual observation effort conducted when Beaufort sea state < 5 was 1,961 km, 1,491 km and 3,243 km respectively. Acoustic records were done when Beaufort sea state < 5 during daylight and/or nighttime, depending on the survey. A total of 132 cetacean sightings were done. Five cetacean families and 15 species were identified. Delphinidae was the family most frequently sighted (91% to 100% of groups and 99% to 100% of individuals per campaign). The most frequent species in the area were identified, along with their distribution and phenology: Guiana dolphin (Sotalia guianensis) was found in the coastal area (0-20 m), the long-beaked common dolphin (Delphinus delphis) was sighted on the shelf (20-100 m), along with the bottlenose dolphin (Tursiops truncatus) and the Atlantic spotted dolphin (Stenella frontalis) that were also common on the upper slope (100-1,500 m). Finally, the spinner dolphin (Stenella longirostris), the melon-headed whale (Peponocephala electra) and the pantropical spotted dolphin (Stenella attenuata) were frequent on the slope (100-3,500 m). The results suggest these species may be found in French Guiana waters all year round and mother and calf pairs, as indicator of reproduction, were observed for all of them except the long-beaked common dolphin and the Guiana dolphin. Mother and calf pairs of humpback whales (Megaptera novaeangliae), that potentially belong to the “A” stock, were also sighted twice, as well as two groups of sperm whales (Physeter macrocephalus) with calves. Hence, these results showed that French Guiana bears a particular responsibility for the conservation of cetacean biodiversity, but a lot remains to be done to strengthen knowledge and conservation of these species in the territory.

Antofagasta Region in northern Chile, a potential nursing ground for the Southern right whale Eubalaena australis

The Chile-Peru subpopulation (CPe) of the Southern right whale (Eubalaena australis) is classified as Critically Endangered following intense whaling in past centuries. Due to their very low abundance, information on breeding and feeding grounds is also scarce. Unmanned aerial vehicles (UAVs) are increasingly applied in marine mammal research thanks to their low cost and relative ease of use. This case study documents a Southern right whale nursing in Bahía Moreno (23º S), Antofagasta, in northern Chile through high-resolution images taken by UAV of an adult in July 2019 and the same whale with a neonate in August. Combined with earlier data we hypothesize that the Antofagasta Region may be a potential calving and nursing ground for the CPe subpopulation. Given the intense shipping traffic and fishing activities around the Mejillones Peninsula and Antofagasta port, priorly recommended marine spatial planning to help avoid net entanglements and vessel collisions of fin and humpback whales may also contribute to the conservation of the CPe stock.

A decade of whale watching in an important tourist desitination in the Pacific coast of Colombia: Challenges for proper management

Uramba Bahía Málaga Natural National Park is one of the most important places visited by tourists to see humpback whales (Megaptera novaeangliae) in Colombia. Humpback whales arrive from Southern Chile and the Antarctic Peninsula every year between May and December to reproduce, give birth and rear calves. To evaluate the current state of whale-watching in Málaga we analyzed tourist visitation data from 2011 to 2019 during the peak whale-watching season (July–October), and during one week in October 2020. We found that whale-watching activity has increased considerably. In 2019, 21,186 tourists realized whale watching in Málaga. Whale watchers per month increased by 108% and monthly whale-watching boat trips increased by 140%, in the last decade. Currently there are in average 19 boat trips per day (±18.0), and most boats are small (≤15 m). Tourists came mainly from Colombia (90%). August was the most important month for whale watching. Although environmental education activities are undertaken, currently responsible whale-watching guidelines are overlooked. At present, whale-watching activity produces important economic benefits for local people and neighboring sites, with a monthly expenditure of at least $362,409 USD, but to ensure the sustainable continuity of this activity, negative impacts on whales need to be minimized. We classified management challenges into social, economic and biological aspects. From a social perspective, operators should form a whale-watching community association; this would improve cooperation amongst operators, promote good practices in whale-watching and reduce pressure on whales. Economic recommendations include 1) whale-watching trips handled mainly by local people; 2) ticket prices unification; and 3) investment in tourist facilities. Biological recommendations focus on the welfare of whales and include: 1) follow the current whalewatching recommendations strictly; 2) reduce transit speeds to below 10 knots in the area during whale season; 3) use propeller guards; 4) promote land-based whale watching; 5) implement acoustic whale tourism; 6) reinforce environmental education programs; and 7) support long-term monitoring and scientific research. Based on these three aspects, we urge environmental and ethnic authorities, conferring with relevant stakeholders, to determine the whale-watching carrying capacity of the area and to promote a responsible tourism. Authorities need to strengthen the monitoring, oversight and control of this growing tourist activity in order to ensure its long-term persistence.

Passive acoustic monitoring of river dolphin (Inia geoffrensis and Sotalia fluviatilis) presence:

All river dolphin species are in decline as a direct result of intensified anthropogenic activity along river systems. In South America, the size and geographical complexity of their range pose a challenge to status assessment. Passive acoustic monitoring offers a cost-effective, scalable, and readily standardized method for determining species distribution and can augment the spatiotemporal coverage of visual survey efforts currently underway. A passive acoustic survey of dolphin presence was conducted in two areas of the Amazon River subject to different degrees of human use; the inland port city Iquitos and the Pacaya-Samiria National Reserve, in Peru. Surveys were based on acoustic detection of biosonar activity. Recorders were distributed at 17 sites along 61 linear km of river habitat for durations of 46 to 148 h. Dolphin presence was 45% lower near the city than in the reserve. This study demonstrates the efficacy of acoustic monitoring as a method for testing dolphin redistribution and/or decline hypotheses in the context of anthropogenic development. The methods are applicable to continuous future monitoring and status assessment of river dolphins in South America as well as in Asia.