Prerpints.org logo
Preprint
Article

Nearshore Migrating Humpback Whales off Metropolitan Lima, Central Peruvian Coast, Underscore Potential Conflict with Fisheries

Altmetrics

Downloads

119

Views

75

Comments

0

This version is not peer-reviewed

Submitted:

29 July 2023

Posted:

31 July 2023

You are already at the latest version

Alerts
Abstract
The notion that ‘Stock-G’ humpback whales off western South America are primarily deep oceanic migrators is poorly supported. We documented 66 land-based sightings from Pucusana, Lima Sur: 18 incidental (2002–2023) and 48 dedicated sightings during the northbound winter migration (June-July 2023), covering respectively 38 and 105 individual whales, despite a mean daily observer effort of only 58.7 min. Estimated distances from shore ranged 20–7,000 m (mean= 2,729 m) at depths 25–99 m, while 50% migrated at < 2,500 m (median) from shore. Several groups skirted the coastline from headland to headland. Of five southbound migrating groups, four included an adult with neonate; no northbound groups enclosed a neonate. Two cases of single juvenile/subadult whales moving multidirectionally and closely associated with large seabird feeding frenzies, were considered foraging also. In 2023, 94% of all northbound nearshore sightings occurred from 14 June-11 July, signalling the maximum threat period for interactions with coastal fisheries off metropolitan Lima. If migration is temporally and spatially predictable, effective mitigating measures should be feasible.
Keywords: 
Subject: Biology and Life Sciences  -   Behavioral Sciences

Introduction

Ramírez (1988) concluded that, off northern Peru, humpback whales Megaptera novaeangliae tend to occur close to shore in the spring. In 1965, a large majority of animals were taken from a shore-based whaling station (Paita) at less than 100 nmiles from shore, and many much closer (Ramírez, 1988). Nearshore occurrence was later confirmed for the northern Peruvian breeding/calving ground in Piura and Tumbes (Pacheco et al., 2009; Santillán, 2011; Silva-Buse and Pacheco, 2016). Other authors (Mackintosh, 1942; Clarke, 1957, 1962; Winn and Reichley, 1985) contended that, regionally, off western South America, humpback whales (HW) are deep oceanic migrators, beyond the 200 m depth line, ‘which could explain the paucity of inshore sightings, except for the tropical breeding grounds’ (Winn and Reichley, 1985). This hypothesis, apparently based on some sightings in Chilean offshore waters, has not been challenged but neither confirmed.
We suggest that the ‘paucity of inshore sightings’ was due to a lack of dedicated coastal observer effort because we here demonstrate that, at least off the central Peruvian coast, consequential numbers of HW migrate nearshore, within 5 nmiles and many much closer, during the northbound migration in austral winter. Since initial evaluations and calls for increased research (Ramírez, 1988; Van Waerebeek et al., 1996) on the IWC-defined 'Breeding Stock G' off Chile, Peru, Ecuador, Colombia and Panama the species has become the most studied mysticete in the region, partly linked to its value as commercial whale-watching target (e.g., Stevick et al., 2004; Pacheco et al., 2009; Silva-Buse and Pacheco, 2016; Flórez-González, 1991; Flórez et al., 2005; Félix et al., 2011; Avila et al., 2017; Guzman and Félix, 2017 and others). Appreciable knowledge has accumulated recently on the ecology, behaviour, abundance and threats in the breeding/calving grounds off northern Peru (Pacheco et al., 2009; Santillán, 2011; García-Godos et al., 2013), Ecuador (Félix et al., 2007, 2011; Guzman and Félix, 2017) and Colombia (Flórez-González, 1991; Capella et al. 2007; Avila et al., 2017), to cite a few. A comprehensive review is beyond the scope of this note, but see others (e.g. Scheidat et al., 2000; Flórez-González et al., 2005; Hucke-Gaete et al., 2013; Acevedo et al., 2017). Latest, unexpected, insights include evidence of feeding in low-latitude locations in Ecuador and northern Chile (García-Cegarra et al., 2021a).
Several authors (e.g., Stevick et al., 2004; Acevedo et al., 2013; Castro et al., 2013) discussed links between northern and austral final destinations of the annual migration of Stock-G, which covers thousands of km between the Antarctic Peninsula and Fuegian feeding grounds and the tropical breeding/calving grounds. However, very little observational information is available on the actual migratory paths and corridors used by HW outside these major feeding and breeding areas. Here we present evidence of substantial numbers of humpback whales migrating in Lima nearshore waters on the central Peruvian coast, and discuss implications.

Material and Methods

Sightings of humpback whales and other cetaceans were recorded both opportunistically (2002–2023) and in dedicated mode (June-15 July 2023) from the observation platform of the Peruvian Centre for Cetacean Research (CEPEC), Pucusana (12°29.0’S,76°48.1’W), located at the southern limit of Metropolitan Lima (Figure 3-A). One 1997 outlier observation was added. The junior author (E.B.C.), who received prior training, participated in data collection within a ‘citizen science’ framework (see García-Cegarra et al., 2021b).
The CEPEC platform is positioned on rocky cliffs ca. 26.0 m above sea level and overlooks an unnamed inlet (henceforth referred to as ‘Whale Inlet’) bordered by two rocky headlands, the Punta Grano de Oro at the southern end and Punta Rostro de Cristo in the north (Figure 3-B). The platform offers an unimpeded 150° view (compass: 158°- 308°) of Whale Inlet, of which 110° (compass: 198°- 308°) is exposed to the open Pacific Ocean. The Punta Grano de Oro headland is at 1,300 m SSW from the platform and was used as reference to estimate distances to whale groups. Estimated water depth was obtained from online bathymetric charts by Navionics (Garmin ®).1
For the period 2002-2022, incidental (opportunistic) observation ‘effort’ was unquantifiable. The probability to detect passing whales by naked eyes evidently was very low. CEPEC occupation typically amounted to ca. 6 months per annum. The opportunistic ‘effort’ was stochastic although a slight bias may exist with higher observation time in summer (when HW are rare) due to favorable weather and visibility.
To improve HW detection, dedicated sighting effort was implemented from 1 June–15 July 2023 (44 effective survey days), when the main northbound migration was estimated to occur. For every hour (08:00–18:00), weather permitting, 5 min were surveyed by naked eye and 10x50 binoculars (Olympus DPS1 6.5°). High-powered 18x50 image-stabilized binoculars (Canon IS UD 3.7°) were used to confirm species ID, group composition and behaviour. With each sighting, the prolonged on-effort time was recorded, as to estimate the relative density of whales (number of whales seen / minute effort).
Data recorded include species, group size (min., max., best estimate), start/stop time of observation, main behaviour, direction, distance from shore (closest and farthest), associated species (especially seabirds), indications of feeding, photos. Main behaviour categories observed included fast travel, slow travel, milling, breaching, lobtailing, flipper-slapping and (rarely) foraging.
Species authentication was based on the distinctive shape of dorsal fin, long flippers, bushy blow, serrated trailing edge of flukes, wheeling surfacing pattern and typical aerial behaviour (Best, 2010; Carwardine, 2020). Two cases of ‘like-humpback whale’ (sensu IWC Scientific Committee), i.e. whales at great distance whose behaviour (e.g. full-body leaps) and the few morphological cues observed were consistent with HW, were included.

Results and Discussion

Seasonality
Opportunistic sightings. Prior to June 2023, 18 opportunistic HW sightings (n=32 individuals), the earliest in 1997, were registered from the CEPEC observer platform. All northbound (n=13) and southbound (n= 5) migrating groups were observed, respectively, in the period 18 June – 21 August and 23 Sept– 23 Feb. The latter, rare, summer sighting concerned a juvenile/subadult moving erratically and closely associated with a large group of foraging seabirds, strongly suggesting it was also feeding.
Dedicated (on-effort) sightings. From 1 June to 15 July 2023, effective daily dedicated observer effort (excluding 2 off-days) amounted to a mean of 58.7 min/day (SD=25.67; n=43; range = 0–145 min; median= 50 min). A total of 48 positive humpback whale groups were documented, with two exceptions (see Feeding behaviour) all of these travelling north and assumed to partake in the northbound winter migration. The total number of whales observed in this 6-week period was 105, summing best estimates of group sizes, with 94% of all HW observed in the 4-week period 14 June-11 July 2023 (see Figure 1 and Figure 2). The climax was on 27 June when 6 sightings were recorded and a total of 21 HW. After 11 July whale observations rapidly decreased.
Group Size and Composition
Data on humpback whale group sizes sighted in Pucusana are summarized in Table 1, separated in three samples (Table 1). Median group size was 2 whales (presumably many of these a female and primary male escort); the largest groups consisted of 5 whales. The detected group sizes are considered highly reliable as typically good views were possible, covering multiple surfacings and monitored through image-stabilized binoculars. The latter often permitted to distinguish between individuals, due to differential body size, dorsal fin shape and behaviour. In a ‘dedicated’ subsample (n= 38), 71.1% consisted of adults or subadults, 26.3% were adult(s) mixed with juvenile(s) and one case (2.6%) was a single juvenile. Many groups synchronized respiration.
Of 5 southbound travelling groups (all opportunistic sightings), 4 included a neonate calf, as determined from its small size (1/3 of adult body), presumably born at one of the known tropical calving grounds in the eastern Pacific (e.g. Scheidat et al., 2000; Flórez-González et al., 2005; Pacheco et al., 2009; Castro et al., 2013).
Distance from Shore
All migrating humpback whale groups were observed moving in inshore waters, within sight of the shoreline, ranging from barely 20 m from the cliffs (water depth: 25–28 m) up to a maximum of 7,000 m (depth: 99 m). Presumably, offshore, deep-water migrations also occur, however undetected through land-based observations like ours, and/or impossible to positively identify to species.
Estimated distance to shore (in m) for the multiple-year sample of opportunistic sightings ranged 30–3,000 (mean= 601.8; SD= 897.2; median= 100), while for the dedicated sightings in June-July 2023, this range was 20–7,000 (mean= 2729.6; SD= 1665.9; median= 2500). These samples were highly significantly different (Mann-Whitney U= 95.5; z-score= 4.613; p<0.001), as expected, considering that for the 2023 sample binoculars were utilized during searches, permitting the spotting of whales at much greater distances. Southbound migrators moved close to shore (range: 50–1,000 m; mean= 330 m; median= 150 m) but the current sample is too small (n= 5) to allow statistical testing.
One group of three whales (one of which was net-entangled, see García-Godos et al., 2013) moved so exceptionally close to the cliffs that the whales were detected (in the office) from the sound of their blows. Another whale breached twice at some 20-25 m from the Punta Rostro de Cristo. Both groups headed north.
Feeding Behaviour
García-Cegarra et al. (2021a) called for further research into the feeding ecology of Stock-G after demonstrating occasional feeding in the Antofagasta area (northern Chile) and in Ecuador. We observed three cases of single individuals of HW moving multi-directionally (unlike migrating whales), in close association with actively feeding seabirds: (i) A juvenile/subadult, in a rare summer sighting (23 February 2023), headed straight into a massive seabird feeding frenzy (mainly Peruvian boobies Sula variegata), locally known as ‘pajarada’ and remained directly associated for at least 20 min. Distance from shore was 400-600 m.
(ii) On 10 June 2023, a single juvenile/subadult, changing course repeatedly continuously (N, S, SW, N again), was thought to be feeding while followed by a foraging pajarada of at least 250 seabirds, many diving (Inca terns Larosterna inca, Peruvian boobies, cormorants Phalacrocorax sp. and band-tailed gulls Larus belcheri). Observation 10:00–10:25. The whale performed 12 leaps, after which observation effort was interrupted. The same individual (cf. white pectorals) was re-sighted 10:47–10:58 some distance north, still breaching and still directly associated with a feeding frenzy of >120 seabirds, mostly diving boobies and cormorants. (iii) An adult whale (13 July 2009), at 100-500m from shore, milling and changing course also appeared to be feeding near the surface (although with lesser certainty). At least (i) and (ii), interestingly both single juveniles/subadults, are considered positive observations of feeding humpback whales, a first for the central Peruvian coast.
Other Parameters
The effective total duration of observation per group was highly variable, depending on both the azimuth (relative to the observation platform) when first spotted and whale behaviour. Duration ranged from 4–61 min (mean= 20.02; SD= 13.12; median= 17).
Other cetacean species observed in June-July 2023 include a Bryde’s whale Balaenoptera brydei, an unidentified, fast-swimming, large balaenopterid (either fin B. physalus or blue whale B. musculus), two other whales (unidentifiable due to great distance), common bottlenose dolphins Tursiops truncatus, and dusky dolphins Lagenorhynchus obscurus.

Discussion

Contrary to earlier assumptions, new evidence firmly indicates that on Peru’s central coast, and more specifically in continental waters off Metropolitan Lima, many ‘Stock G’ humpback whales migrate nearshore, and can be observed from land. We estimated that for the recorded neritic migrators, 50% (50th percentile) migrate north within 2,500 m from shore, and among these an appreciable number may actually skirt the coastline from headland to headland. Another proportion of HW likely migrate further offshore in continental shelf waters, perhaps including deep oceanic waters, but evidently this cannot be determined through land-based studies. Allen (2013) investigated the roles of geomagnetic and acoustic cues in HW navigation and orientation, but potential visual cues were not studied in any detail. Considering it physically possible, we suggest that nearshore migrating HW may also use visual cues for navigation, such as rocky promontories and other topographic landmarks. Full-body leaps (breaching), which were frequent, perhaps may allow whales to visually locate headlands and thus determine shortest routes. On several occasions, whales closely rounded Pta. Grano de Oro and then crossed Whale Inlet in a straight line north towards Pta. Rostro de Cristo (Figure 3). The proportions of HW that engage in nearshore and offshore migratory paths towards/from the tropical breeding/calving grounds should be determined. To increase the nearshore dataset the present dedicated land-based survey effort should be continued, and in particular also the return spring journey should be monitored.
No neonate calves were seen during northbound migration, consistent with the absence of a calving ground south of Lima. The coasts of Piura, northern Peru, are presently understood to constitute the austral-most breeding/calving grounds for ‘Stock G’ humpback whales (Pacheco et al., 2009; Santillán, 2011; Silva-Buse and Pacheco, 2016). In contrast, neonate-sized calves were observed in four of five southbound going HW groups, travelling at a mean distance of 312 m. We hypothesize that mother-calf pairs preferentially may choose very nearshore paths, and use the shoreline and shallow water as physical barriers against predators. However, this requires confirmation.
The nearshore migration occurs despite the dense small-vessel traffic observed, including large numbers of artisanal gillnet fishing craft and industrial purse-seiners. No indications of vessel avoidance behaviour were detected, nor did fishing boats avoid whales. Its nearshore occurrence may help explain why the HW is the whale species most vulnerable to net entanglements in Peru. Records show that HW accounts for 66.7 % of whales involved in lethal net entanglement cases in Peru. Ten cases were documented up to 2012 (Valdivia and Ramírez, 1981; García-Godos et al., 2013) but unfortunately many new records exist. Lethal entanglement as well as ship collisions have also been recorded from the high-density HW breeding/calving ground around Isla de la Plata, Ecuador (Félix and Van Waerebeek, 2005; Félix et al., 2007; 2011) and Isla Gorgona, Colombia (Capella et al., 2001; Flórez-González et al., 2005; Avila et al., 2017). Generally, G-Stock has been severely affected by fishery interactions, with an estimated rate of 32 net entanglements per year in Ecuador in the period 2004–2006 (Félix et al. 2007; 2011) and a mean of 2.8 entanglements per year in Colombia in 1996–2006 (Capella et al., 2001, 2007), most with lethal outcome. No estimates exist for Peru and Chile but the wide spatial and temporal distribution of entanglements in Peru (García-Godos et al., 2013) suggests that both breeding and migrating whales are affected. The finding that significant numbers of humpback whales migrate so close to shore underscores the obvious threat of severe interactions with inshore operating artisanal fisheries. We strongly recommend that dedicated land-based observations should be continued, including if possible monitor from an additional station such as in Chorrillos or Miraflores. A future migration cycle during a non-El Niño year should also be observed as to compare with the present El Niño year, in an attempt to deduct whether ENSO events have, or not, a significant impact on spatial and temporal distribution of humpback whales in Peruvian waters. Finallly, marine environment managers and conservationists should consider launching an awareness building campaign in coastal Peru, and invite fishermen to duly report all cases of whale net entanglements and vessel-whale collisions and comment on the outcome for both whales and fishers’ gear.

Acknowledgements

K.V.W. is grateful to Pro Delphinus (Lima, Peru) for general support. The Centro Peruano de Estudios Cetológicos (CEPEC) is an all-volunteer working group studying aspects of cetacean conservation biology in the Eastern South Pacific, as well as globally.

Conflicts of Interest

The authors declare no conflicting interests related to any aspect of this scientific note.
1
https://webapp.navionics.com

References

  1. Acevedo, J.; Haro, D.; Dalla-Rosa, L.; Aguayo-Lobo, A.; Hucke-Gaete, R.; Secchi, E.; . . . Pastene, L. A. Evidence of spatial structuring of eastern South Pacific humpback whale feeding grounds. Endangered Species Research 2013, 22, 33–38. [CrossRef]
  2. Allen, A.N. (2013) An investigation of the roles of geomagnetic and acoustic cues in whale navigation and orientation. Ph.D. Thesis, Massachusetts Institute of Technology. Publication Number: AAT 0829318; Dissertation Abstracts International, Volume: 74-11(E), Section: B.
  3. Avila, I. C.; Correa, L. M.; Van Waerebeek, K. Where humpback whales and vessel traffic coincide, a Colombian Pacific case study. Boletín del Museo Nacional de Historia Natural, Chile 2017, 66, 11–19. [Google Scholar]
  4. Best, P. B. 2010. Whales and Dolphins of the Southern African Subregion. Cambridge University Press, Cape Town, South Africa. 338pp.
  5. Capella, J.; Flórez-González, L.; Falk, P. Mortality and anthropogenic harassment of humpback whales along the Pacific coast of Colombia. Memoirs of the Queensland Museum 2001, 47, 547–553. [Google Scholar]
  6. Capella, J.; Flórez-González, L.; Herrera, J.; Falk, P. and Tobón, I. (2007). Captura incidental e intencional de grandes cetáceos en Colombia. Pp. 94–98. In: F. Félix (ed.). Memorias del taller de trabajo sobre el impacto de las actividades antropogénicas en mamíferos marinos en el Pacífico sudeste. 28 –29 November 2006, Bogotá. Comisión Permanente del Pacífico Sur/Programa de las Naciones Unidas para el Medio Ambiente (CPPS/PNUMA), Guayaquil. 29 November.
  7. Carwardine, M. (2020) Handbook of whales, dolphins and porpoises. Bloomsbury Wildlife, Bloomsbury Publishing Plc. London, UK. 528 pp.
  8. Castro, C.; Aguayo-Lobo, A.; Allen, J.; et al. (2013) Humpback whale identification off Ecuador and their migratory connections to Antarctica (Area I And II). Paper SC/64/SH23 presented to the 64th Scientific Committee of the International Whaling Commission, Panama City, Panama. 5pp.
  9. Clarke, R. W. Whale observation and whale marking off the coast of Chile and from Ecuador towards and beyond the Galapagos Islands in 1959. Norsk Hvalfangst- Tidende 1962, 7, 265–287. [Google Scholar]
  10. Clarke, R. W. Catches of sperm whales and whalebone whales in the Southeast Pacific between 1908 and 1975. Rep. Int. Whal. Commn. 1980, 30, 285–288. [Google Scholar]
  11. Félix, F.; Van Waerebeek, K. Whale mortality from ship strikes In Ecuador and West Africa. LAJAM 2005, 4, 55–60. [Google Scholar] [CrossRef]
  12. Félix, F.; Samaniego, J.; Haase, B. (2007) Interacción de cetáceos con la pesquería artesanal pelágica en Ecuador. Pp. 50 – 54 In: F. Félix, ed. Memorias del taller de trabajo sobre el impacto de las actividades antropogénicas en mamíferos marinos en el Pacífico sudeste. 28– 29 November 2006, Bogotá. Comisión Permanente del Pacífico Sur/Programa de las Naciones Unidas para el Medio Ambiente (CPPS/PNUMA), Guayaquil. 29 November.
  13. Félix, F.; Muñoz, M.; Falconi, J.; Botero, N.; Haase, B. Entanglement of humpback whales in artisanal fishing gear in Ecuador. J. Cetacean Res. Manag. 2011, 285–290. [Google Scholar] [CrossRef]
  14. FIórez-González, L. Humpback whales Megaptera novaeangliae in the Gorgona Island, Colombian Pacific breeding waters: population and pod characteristics. Memoirs of the Queensland Museum 1991, 30, 291–295. [Google Scholar]
  15. Flórez-González, L.; Avila, I.C.; Capella-Alzueta, J.; Falk, P.; Félix, F.; Gibbons, J.; Guzmán, H.M.; Haase, B.; Herrera, J.C.; Peña, V.; Santillán, L.; Tobón, I.C.; Van Waerebeek, K. (2005) Estrategía de conservación de la ballena jorobada en el Pacífico sureste. Lineamientos para un plan de acción regional e iniciativas nacionales. World Wildlife Fund and Yubarta, Cali, Colombia. 106 pp.
  16. García-Cegarra, A.M.; Castro, C.; Van Waerebeek, K. Feeding of humpback whales in low latitudes of the Southeast Pacific Ocean. Neotropical Biodiversity 2021, 7, 421–430. [Google Scholar] [CrossRef]
  17. García-Cegarra, A.M.; Toro, F.; Gonzalez-Borasca, V. Citizen science as a tool to assess cetacean diversity in the Atacama Desert coast. Ocean and Coastal Management 2021, 213, 105858. [Google Scholar] [CrossRef]
  18. García-Godos, I.; Van Waerebeek, K.; Alfaro-Shigueto, J.; Mangel, J. Entanglements of large cetaceans in Peru: Few records but high risk. Pacific Science 2013, 67, 523–532. [Google Scholar] [CrossRef]
  19. Guzmán, H.; Félix, F. Movements and habitat use by southeast Pacific humpback whales satellite tracked at two breeding sites. Aquatic Mammals 2017, 43, 139–155. [Google Scholar] [CrossRef]
  20. Hucke-Gaete, R.; Haro, D.; Torres-Florez, J.P.; et al. A historical feeding ground for humpback whales in the Eastern South Pacific revisited: the case of northern Patagonia, Chile. Aquatic Conservation: Marine and Freshwater Ecosystems 2013, 23, 858–867. [Google Scholar] [CrossRef]
  21. Mackintosh, N.A. The southern stocks of whalebone whales. Discovery Reports 1942, 22, 197–300. [Google Scholar]
  22. Matthews, L.H. The humpback whale, Megaptera nodosa. Discovery Reports 1937, 17, 7–92. [Google Scholar]
  23. Pacheco, A.; Silva, S.; Alcorta, B. Winter distribution and group composition of humpback whales (Megaptera novaeangliae) off northern Peru. Latin Am. J. Aquat. Mamm. 2009, 7, 33–38. [Google Scholar] [CrossRef]
  24. Ramírez, P. La ballena jorobada Megaptera novaeangliae en la costa Norte del Perú [The humpback whale Megaptera novaeangliae on the northern coast of Peru]. Boletín de Lima 1988, 56, 91–96. [Google Scholar]
  25. Santillán, L. Records of humpback whales (Megaptera novaeangliae) in Sechura Bay, Peru, in spring 2009-2010. Journal of Marine Animals and Their Ecology 2011, 1, 29–35. [Google Scholar]
  26. Scheidat, M.; Castro, C.; Denkinger, J.; et al. A breeding area for humpback whales (Megaptera novaeangliae) off Ecuador. J Cetac Res Manag. 2000, 2, 165–172. [Google Scholar] [CrossRef]
  27. Silva-Buse, S. and Pacheco, A.S. (2016). Ballenas en el norte del Perú. Whales of Northern Peru. Fondo Editorial Universidad Científica del Sur, Lima, Peru. 173pp.
  28. Stevick, P.T.; Aguayo, A.; Allen, J.; Avila, I.C.; Capella, J.; Castro, C.; Chater, K.; Dalla Rosa, L.; Engel, M.H.; Felix, F. Migrations of individually identified humpback whales between the Antarctic Peninsula and South America. J. Cetacean Res. Manage. 2004, 6, 109–113. [Google Scholar] [CrossRef]
  29. Valdivia, J.; Ramírez, P. Peru progress report on cetacean research, June 1979 –May 1980. Rep. Int. Whaling Comm. 1981, 31, 211–214. [Google Scholar]
  30. Van Waerebeek K., Alfaro-Shigueto J. and Arias-Schreiber M. (1996) Humpback whales off Peru: new records and a rationale for renewed research. Document SC/48/SH1 presented to the International Whaling Commission Scientific Committee, June 1996, Aberdeen, UK. 8pp. 19 June.
  31. Winn, H.E. and Reichley, N. E. (1985) Humpback whale - Megaptera novaeangliae. Pp. 241-273. In: (eds.) S.H. Ridgway and R. Harrison. Handbook of Marine Mammals, Vol.3. Academic Press. 362pp.
Preprints 80916 g001
Figure 1. Daily number of northbound migrating humpback whales observed off Pucusana, Lima, in the period 1 June–15 July 2023.
Figure 1. Daily number of northbound migrating humpback whales observed off Pucusana, Lima, in the period 1 June–15 July 2023.
Preprints 80916 g001
Preprints 80916 g002
Figure 2. Daily humpback whale relative density (per minute observation effort) off Pucusana, Lima, for the period 1 June–15 July 2023.
Figure 2. Daily humpback whale relative density (per minute observation effort) off Pucusana, Lima, for the period 1 June–15 July 2023.
Preprints 80916 g002
Preprints 80916 g003
Figure 3. (A) Location of the Pucusana fishing port at the southern limit of Metropolitan Lima. (B) Map of the study area showing topography of the coastline in the vicinity of the CEPEC observation platform. The southern (Punta Grano de Oro) and northern boundaries (Punta Rostro de Cristo) of the monitored waters are indicated. Modified from OpenSeaMap (Marble Virtual Globe, Version 2.2.20).
Figure 3. (A) Location of the Pucusana fishing port at the southern limit of Metropolitan Lima. (B) Map of the study area showing topography of the coastline in the vicinity of the CEPEC observation platform. The southern (Punta Grano de Oro) and northern boundaries (Punta Rostro de Cristo) of the monitored waters are indicated. Modified from OpenSeaMap (Marble Virtual Globe, Version 2.2.20).
Preprints 80916 g003
Table 1. Descriptive statistics for humpback whale group sizes (best estimates) recorded off Pucusana, Lima, Peru. Opportunistic records cover multiple years; dedicated (on-effort) records are from June-July 2013 only.
Table 1. Descriptive statistics for humpback whale group sizes (best estimates) recorded off Pucusana, Lima, Peru. Opportunistic records cover multiple years; dedicated (on-effort) records are from June-July 2013 only.
Preprints 80916 i001
Disclaimer/Publisher’s Note: The statements, opinions and data contained in all publications are solely those of the individual author(s) and contributor(s) and not of MDPI and/or the editor(s). MDPI and/or the editor(s) disclaim responsibility for any injury to people or property resulting from any ideas, methods, instructions or products referred to in the content.
Copyright: This open access article is published under a Creative Commons CC BY 4.0 license, which permit the free download, distribution, and reuse, provided that the author and preprint are cited in any reuse.
Prerpints.org logo

Preprints.org is a free preprint server supported by MDPI in Basel, Switzerland.

facebook logotwitter logolinkedin logo
MDPI Initiatives
Important Links
Subscribe

Disclaimer

Terms of Use

Privacy Policy

© 2024 MDPI (Basel, Switzerland) unless otherwise stated