We show that humpback-whale vocalization behavior is synchronous with peak annual Atlantic herring spawning processes in the Gulf of Maine. With a passive, wide-aperture, densely-sampled, coherent hydrophone array towed north of Georges Bank in a Fall 2006 Ocean Acoustic Waveguide Remote Sensing (OAWRS) experiment, vocalizing whales could be instantaneously detected and localized over most of the Gulf of Maine ecosystem in a roughly 400-km diameter area by introducing array gain, of 18 dB, orders of magnitude higher than previously available in acoustic whale sensing. With humpback-whale vocalizations consistently recorded at roughly 2000/day, we show that vocalizing humpbacks (i) were overwhelmingly distributed along the northern flank of Georges Bank, coinciding with the peak spawning time and location of Atlantic herring, and (ii) their overall vocalization behavior was strongly diurnal, synchronous with the formation of large nocturnal herring shoals, with a call rate roughly ten-times higher at night than during the day. Humpback-whale vocalizations were comprised of (1) highly diurnal non-song calls, suited to hunting and feeding behavior, and (2) songs, which had constant occurrence rate over a diurnal cycle, invariant to diurnal herring shoaling. Before and during OAWRS survey transmissions: (a) no vocalizing whales were found at Stellwagen Bank, which had negligible herring populations, and (b) a constant humpback-whale song occurrence rate indicates the transmissions had no effect on humpback song. These measurements contradict the conclusions of Risch et al. Our analysis indicates that (a) the song occurrence variation reported in Risch et al. is consistent with natural causes other than sonar, (b) the reducing change in song reported in Risch et al. occurred days before the sonar survey began, and (c) the Risch et al. method lacks the statistical significance to draw the conclusions of Risch et al. because it has a 98–100% false-positive rate and lacks any true-positive confirmation.
In agriculture, a rising number of sustainability assessments are available that also comprise financial ratios. In a literature review of farm management textbooks, taking account of the differences between European and North American practices and considering prevalent sustainability assessment approaches, we identified frequently used financial ratios. Five ratios relate to the indicator profitability and four to the indicator liquidity. Another eight financial indicators refer to the indicators financial efficiency, stability, solvency and repayment capacity. Based on more than 14,000 accountancies of dairy farms from the Swiss Farm Accountancy Data Network (FADN), we carried out a Spearman correlation analysis for normalised and harmonised financial ratios. The correlation analysis revealed mostly positive correlations. To assess the implementation of a quantitative economic sustainability assessment we compare an aggregated indicator compound of all 17 ratios with two selections of financial ratios–first, a compound European and, second, a compound North American economic sustainability indicator. The correlation between the complete and the reduced sets of indicators suggest that both aggregate economic indicators can be reasonably applied to estimate the economic sustainability for Swiss dairy farms.
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