Magdalena-Puyuhuapi IMMA

Criterion A – Species or Population Vulnerability

Chilean dolphins (Cephalorhynchus eutropia) are endemic to south-central and southern Chile and are listed as Near Threatened (NT) on the IUCN Red List (Heinrich and Reeves, 2017). Range-wide abundance is not known but the entire species is thought to number in the low thousands which, if confirmed, would meet the criteria for Vulnerable (VU) status (Heinrich and Reeves, 2017). Chilean dolphins in the southern fjord region are considered genetically distinct from those along the open coast to the north of Chiloé (Pérez-Alvarez et al., 2015). The exact genetic boundary remains unclear due to a 500 km gap in sampling locations. The Magdalena-Puyuhuapi population falls within this sampling gap. Chilean dolphins have become entangled and drowned in the nets of open-pen fish farms that abound in the Tenth (Xth) Region of Chile (in which this IMMA is located), and in Canal Puyuhuapi in particular (Espinosa-Miranda et al, 2019). Regular bycatch of only a few individuals could have negative effects on the small local dolphin population (estimated to be less than <100 individuals) (Pérez-Alvarez et al., 2021). Criterion B: Distribution and Abundance

Sub-criterion B1: Small and Resident Populations

There has been limited systematic marine mammal survey effort in Canal Puyuhuapi. However, sightings of Chilean dolphins have been recorded in the same locations near Puyuhuapi and off Isla Magdalena over several decades (Zamorano-Abramson et al., 2010; Boldt Corvalán, 2016; Heinrich, 2021; Pérez-Alvarez et al., 2021; Heinrich et al., in prep). Several tourism operators include the Magdalena Island coast in their half-day boat tours and report regular sightings of Chilean dolphins in the same area during the summer (Syndicate of Tour Operators in Puerto Cisnes, pers. comm; Boldt Corvalán, 2016). Chilean dolphin sightings are limited to the shallow waters within a few hundred meters, off the coast, the upper channel and river mouths (Zamorano-Abramson et al. 2010, Boldt Corvalán, 2016, Heinrich, 2021, Heinrich et al., in prep, Pérez-Alvarez et al., 2021). Dedicated photo-identification mark recapture surveys have yielded estimates of 42 adult Chilean dolphins in the upper Puyuhuapi Channel (Heinrich and Espinosa-Miranda, 2019; Heinrich, 2021; Heinrich et al., in prep) and 55 adult individuals in the Puerto Cisnes-Magdalena area (Pérez-Alvarez et al., 2021). Some individuals identified in the upper channel were resighted off Magdalena two years later, indicating some movement across the entire channel area. Mother-calf pairs were concentrated off Magdalena Island and particularly in the upper part of the Magdalena Inlet. There are intensive salmon farming operations in Canal Puyuhuapi overlapping substantially with the preferred shallow-water habitat of Chilean dolphins. At least one Chilean dolphin became entangled and drowned in a salmon farm net near Puyuhuapi (Espinosa-Miranda et al., 2019).

Sub-criterion B2: Aggregations

Peale’s dolphins (Lagenorhynchus australis) frequent the shallow nearshore environment along the entire Puyuhuapi Channel with notable concentrations of sightings in the upper channel, in the Queulat inlet as well off the south-western coast of Magdalena Island and north of Puerto Cisnes (Heinrich, 2021; Zamorano- Abramson et al., 2010). No photo-ID studies have been conducted to ascertain population size or individual movements. Tourism operators report regular sightings of Peale’s dolphins off Queulat inlet and north of Puerto Cisnes (Syndicate of Tour Operators in Puerto Cisnes, pers. comm; Boldt Corvalán, 2016). During a short-term pilot study off Puerto Cisnes, Peale’s dolphins were the most frequently observed cetacean species (Boldt Corvalán, 2016). Observations from region-wide surveys indicate that Peale’s dolphins are only seen occasionally in the channels outside the IMMA area (Zamorano-Abramson et al., 2010; Hucke-Gaete et al., 2021), which contrasts with the regular repeated observations of Peale’s dolphins inside the IMMA area.