ALBERT

Description: Sei whales (Balaenoptera borealis) is the least known whale species. Information on sei whale´s vocalizations in the south-eastern Pacific Ocean and its regional variability are even more scarce than that from other ocean areas. This research presents the first characterization of sei whale sounds recorded in Chile during austral autumn of 2016 and 2017. A total of 41 calls have been attributed to sei whale’s downsweeps. In 2016, calls ranged from an average maximum frequency of 105.3Hz down to an average minimum 35.6Hz over 1.6s with a peak frequency of 65.4Hz. During 2017, calls ranged from an average maximum frequency of 93.3Hz down to 42.2Hz (over 1.6s) with a peak frequency of 68.3Hz. The absolute minimum frequency recorded was 30Hz and the absolute maximum frequency was 129.4Hz. Calls generally occurred in pairs, but triplets or singles were also registered. These low frequency sounds share characteristics with recordings of sei whales near the Hawaii Islands, but with differences in the maximum frequencies and duration. These calls distinctly differ from sounds previously described for sei whales in the Southern Ocean and are the first documented sei whale calls in the South-eastern Pacific.

Description: The sei whale (Balaenoptera borealis) is one of the least known whale species. Information on sei whale distributions and its regional variability in the south-eastern Pacific Ocean are even more scarce than that from other areas. Vocalizations of sei whales from this region are not described yet. This research presents the first characterization of sei whale sounds recorded in Chile during the austral autumn of 2016 and 2017. Recordings were done opportunistically. A total of 41 calls were identified to be sei whale downsweeps. In 2016, calls ranged from an average maximum frequency of 105.3 Hz down to an average minimum of 35.6 Hz over 1.6 s with a peak frequency of 65.4 Hz. During 2017, calls ranged from an average maximum frequency of 93.3 down to 42.2 Hz (over 1.6 s) with a peak frequency of 68.3 Hz. The absolute minimum frequency recorded was 30 Hz and the absolute maximum frequency was 129.4 Hz. Calls generally occurred in pairs, but triplets or singles were also registered. These low-frequency sounds share characteristics with recordings of sei whales near the Hawai'ian Islands but with differences in the maximum frequencies and duration. These calls distinctly differ from sounds previously described for sei whales in the Southern Ocean and are the first documented sei whale calls in the south-eastern Pacific.

Description: Magellania venosa, the largest recent brachiopod, occurs in clusters and banks in high abundances of up to 416 ind m-2 in the fjord Comau, northern Chilean fjord region. At some stations, it numerically dominates the subtidal benthic community below 15 m depth, competing for space with the mytillid Aulacomya atra. To determine the question why Magellania venosa is a successful competitor, the brachiopod’s in situ growth rate was studied and its overall growth performance was compared with that of other brachiopods and mussels. The length growth was measured between Februay 2011 and March 2012 after mechanical tagging and Calcein staining. Settlement and juvenile growth were determined from recruitment tiles installed in 2009 and from subsequent photocensus. Growth of Magellania venosa is best described by the general von Bertalanffy growth function, with a maximum shell length (L∞) of 71.53 mm and a Brody growth constant (K) of 0.336 yr-1. The growth rate is the highest recorded for a rynchonelliform brachiopod. Maximal individual somatic production (PInd) is 0.29 g AFDM ind-1 yr-1 at 42 mm shell length and annual production ranges from 1.28 – 89.25 g AFDM yr-1 m-2. The high shell growth rate of Magellania venosa, together with its high overall growth performance may explain the high abundances of this brachiopod in the fjord Comau. However, the somatic production per biomass of the population ( -ratio) is low (0.535) and Magellania venosa may play a minor role in the food chain. Settling behaviour indicates that Magellania venosa is a pioneer species with low juvenile mortality. The brachiopod-bivalve coexistence suggests that neither the presence of potential brachiopod predators nor space competitors (i.e. mytiilids) affect the survival of the brachiopod population.

Description: Cold-water corals are known to grow much slower than their tropical counterparts. However, this assumption is mainly based on laboratory measurements exposing specimens to conditions that differ from their natural environments. The cosmopolitan scleractinian Desmophyllum dianthus forms dense banks below 18min northern Patagonia, Chile. So as to measure in situ growth rates of this cold-water coral, specimens were collected from two sites, weighed and deployed on holders in their natural headlong orientation at the respective collecting site. Corals exhibited a calcium carbonate (CaCO3) mass increase of 5.44+/-3.45 (mg (cm2 projected calyx area)^-1 day^-1) after 2 weeks, equivalent to a mass gain of 0.25+/-0.18 s.d. % day^-1. In comparison, D. dianthus specimens from the same collection sites maintained in an on-site flow-through aquarium system showed lower growth rates that were third of the in situ rates. In situ CaCO3 precipitation of D. dianthus extrapolated for 1 year (kg m^2 year^-1) displays the same order of magnitude as reported for massive growing tropical scleractinians, e.g. Porites sp.