NEW YORK (TheStreet) -- Dry-bulk shipping stocks continued to slide Tuesday, some reaching new 52-week lows, despite what had been a strengthening trend in freight rates.

As one trader pointed out Tuesday, shares of Genco Shipping & Trading ( GNK - Get Report), which had until recently traced the fluctuations in the Baltic Dry Index, which itself tracks spot rates across a number of dry-cargo vessel classes, have decoupled from the BDI. Genco shares have slid so sharply that its price Tuesday, $15.66, indicated a BDI level of about 1,000, this trader said.

The Baltic Dry Index Tuesday stood at 3,579, down 4% from the previous reading. The going rate per day for a Capesize ship, the largest dry-bulk haulers on the high seas, slipped to about $48,000 after having reached nearly $60,000 last week. A year ago, by comparison, amid a surging Chinese importation frenzy, capesize rates were at $72,000 a day.

Genco shares, which have declined 35% since the beginning of May, notched a new 52-week low on Tuesday. The stock was changing hands in recent trades at $15.59, down 52 cents, or 3.2%, after earlier falling as far as $15.18.

Motivations for the steep decline in dry-bulk stocks Tuesday -- and the last few weeks -- have pointed to risk aversion amid highly uncertain times. For one thing, the euro-zone debt crisis has pushed the U.S. dollar ever higher, weighing on commodities prices and commodities-linked stocks, especially high-beta dry-bulk stocks.

For another thing, the world remains skittish about a slower-growing China and just what that will mean for commodities, as economic recovery in the U.S. and Europe doesn't look robust enough to make up for an even slightly weaker China, by far and away the world's most rapacious consumer of raw materials.

Strangely, though, during Tuesday's session, mining shares were sharply stronger across the board. Dry-bulk stocks generally trade in tandem with the shares of companies that extract the materials that the shippers haul.

In related news, with the new quarterly iron-ore pricing system now in full swing, BHP Billiton ( BHP and Rio Tinto ( RTP have reportedly struck their third-quarter agreement with Japanese steelmakers, locking in a price tag of $147 per ton, up 23% from the previous quarter.

The miners were evidently able to drive home price hikes despite weaker global steel prices. Indeed, spot prices for Chinese rebar declined to their lowest point since March, adding to the bleakness among shipping investors. Explained Omark Nokta in a note to clients Tuesday, "Higher iron ore prices for next quarter could further hinder the dry-bulk market, especially with steel prices coming under pressure."

Among other dry-bulk names, DryShips stock fell more than 6% to $3.19 intraday -- a new 52-week low -- as investors were doubly uninterested in owning a dry-bulk shipper combined with a deepwater oil-rig operator.

Diana Shipping also fell to a new low Tuesday: $11.77, down 54 cents, or 4.4% from the previous close.

Among other names, Eagle Bulk Shipping ( EGLE - Get Report) was losing 5.6% in afternoon trades, Excel Maritime ( EXM was down 3.9%, and Navios Maritime ( NM - Get Report) was shedding 2.9%.

-- Written by Scott Eden in New York

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Scott Eden has covered business -- both large and small -- for more than a decade. Prior to joining TheStreet.com, he worked as a features reporter for Dealmaker and Trader Monthly magazines. Before that, he wrote for the Chicago Reader, that city's weekly paper. Early in his career, he was a staff reporter at the Dow Jones News Service. His reporting has appeared in The Wall Street Journal, Men's Journal, the St. Petersburg (Fla.) Times, and the Believer magazine, among other publications. He's also the author of Touchdown Jesus (Simon & Schuster, 2005), a nonfiction book about Notre Dame football fans and the business and politics of big-time college sports. He has degrees from Notre Dame and Washington University in St. Louis.